U.S. patent application number 12/171494 was filed with the patent office on 2010-01-14 for roofing shingle with polymer film backing.
Invention is credited to Edward R. Harrington, JR..
Application Number | 20100005745 12/171494 |
Document ID | / |
Family ID | 41503869 |
Filed Date | 2010-01-14 |
United States Patent
Application |
20100005745 |
Kind Code |
A1 |
Harrington, JR.; Edward R. |
January 14, 2010 |
ROOFING SHINGLE WITH POLYMER FILM BACKING
Abstract
A roofing shingle is a composite sheet which includes a roofing
substrate having a front side and a back side. An asphalt material
impregnates the substrate and coats at least the front side of the
substrate. A polymer film is attached to the back side of the
substrate and forms a back surface of the roofing shingle. The
polymer film was applied to the substrate in the form of a film.
The roofing shingle does not include backdust on the back surface.
The composite sheet is formed into the size and shape of the
roofing shingle. A method of manufacturing roofing shingles
includes continuously supplying a roofing substrate having a front
side and a back side. An asphalt material is applied to the
substrate so that it impregnates the substrate and coats at least
the front side of the substrate. A composite sheet is produced by
providing a polymer film and attaching the polymer film to the back
side of the substrate in a manner that avoids applying backdust to
the substrate so that the polymer film forms a back surface of the
composite sheet. The composite sheet is cut into roofing shingles
while maintaining the back surface free of backdust.
Inventors: |
Harrington, JR.; Edward R.;
(Toledo, OH) |
Correspondence
Address: |
OWENS CORNING
2790 COLUMBUS ROAD
GRANVILLE
OH
43023
US
|
Family ID: |
41503869 |
Appl. No.: |
12/171494 |
Filed: |
July 11, 2008 |
Current U.S.
Class: |
52/409 ;
52/745.19 |
Current CPC
Class: |
E04D 2001/005 20130101;
E04D 1/20 20130101 |
Class at
Publication: |
52/409 ;
52/745.19 |
International
Class: |
E04B 7/00 20060101
E04B007/00 |
Claims
1. A roofing shingle which is a composite sheet comprising: a
roofing substrate having a front side and a back side; an asphalt
material impregnating the substrate and coating at least the front
side of the substrate; and a polymer film attached to the back side
of the substrate and forming a back surface of the roofing shingle,
the polymer film having been applied to the substrate in the form
of a film; the roofing shingle not including backdust on the back
surface; the composite sheet being formed into the size and shape
of the roofing shingle.
2. The roofing shingle of claim 1 wherein the polymer film is
attached to the substrate with substantially none of the asphalt
material between the film and the substrate.
3. The roofing shingle of claim 2 wherein the polymer film is
attached to the substrate by an adhesive.
4. The roofing shingle of claim 2 wherein the polymer film is
attached to the substrate by the surface of the film having been
softened so that it adheres to the substrate.
5. The roofing shingle of claim 1 wherein the asphalt material is
also disposed on the back side of the substrate, and the asphalt
material adheres the polymer film to the substrate.
6. The roofing shingle of claim 1 further comprising roofing
granules applied to the asphalt material coating the front side of
the substrate.
7. The roofing shingle of claim 1 consisting of the substrate, the
asphalt material, the polymer film, optionally roofing granules,
and optionally adhesive.
8. The roofing shingle of claim 1 wherein the substrate is a
relatively lightweight substrate weighing not more than about 1.6
lb/100 ft.sup.2, the polymer film having sufficient strength to
maintain the strength of the roofing shingle with the lightweight
substrate.
9. The roofing shingle of claim 1 wherein the polymer film has a
thickness within a range of from about 0.05 mil to about 10
mils.
10. The roofing shingle of claim 1 wherein the polymer film has a
thickness within a range of from about 10 mils to about 35
mils.
11. The roofing shingle of claim 1 wherein the polymer film is made
from a polyolefin, a polyester, or a blend thereof.
12. A method of manufacturing roofing shingles comprising:
continuously supplying a roofing substrate having a front side and
a back side; applying an asphalt material to the substrate so that
it impregnates the substrate and coats at least the front side of
the substrate; producing a composite sheet by providing a polymer
film and attaching the polymer film to the back side of the
substrate in a manner that avoids applying backdust to the
substrate so that the polymer film forms a back surface of the
composite sheet; and cutting the composite sheet into roofing
shingles while maintaining the back surface free of backdust.
13. The method of claim 12 wherein the polymer film is attached to
the substrate with substantially none of the asphalt material
between the film and the substrate.
14. The method of claim 13 wherein the polymer film is attached to
the substrate by an adhesive.
15. The method of claim 13 wherein the polymer film is attached to
the substrate by softening the surface of the film so that it
adheres to the substrate.
16. The method of claim 12 wherein the asphalt material is also
disposed on the back side of the substrate, and the asphalt
material adheres the polymer film to the substrate.
17. The method of claim 12 further comprising embedding roofing
granules in the asphalt material coating the front side of the
substrate.
18. The method of claim 12 consisting of supplying the substrate,
applying the asphalt material, attaching the polymer film,
optionally applying roofing granules to the asphalt material
coating the front side of the substrate, and optionally using an
adhesive to attach the film.
19. The method of claim 12 wherein the substrate supplied is a
relatively lightweight substrate weighing not more than about 1.6
lb/100 ft.sup.2, and the polymer film attached has sufficient
strength to maintain the strength of the roofing shingle with the
lightweight substrate.
20. The method of claim 12 wherein the polymer film which is
attached has a thickness within a range of from about 0.05 mil to
about 10 mils.
21. The method of claim 12 wherein the polymer film which is
attached has a thickness within a range of from about 10 mils to
about 35 mils.
22. The method of claim 12 wherein the polymer film is made from a
polyolefin, a polyester, or a blend thereof.
Description
TECHNICAL FIELD
[0001] This invention relates to building construction materials
and more particularly to asphalt roofing shingles.
BACKGROUND OF THE INVENTION
[0002] In a typical roofing shingle manufacturing process, a
continuous roofing substrate, such as a glass fiber mat or an
organic felt, is passed into contact with a coater where it is
impregnated and coated with a molten asphalt material. Roofing
granules are applied on the front surface of the coated substrate.
The coated substrate is cooled and then cut into individual
shingles.
[0003] Typically a fine particulate material known as a "backdust"
is applied on the back surface of the coated substrate. The
backdust prevents the roofing shingles from sticking together when
they are stacked in a bundle. Some examples of particulate
materials that have been used include sand, talc and other crushed
rocks or minerals.
[0004] U.S. Patent Application Publication No. 2007/0218250 A1
assigned to Elk Premium Building Products, published Sep. 20, 2007,
discloses roofing shingles that are made without a backdust
material. The roofing shingles include a substrate, an asphalt
material coating the front side of the substrate, and roofing
granules disposed on the asphalt material coated on the substrate.
The shingles also include a hot melt material, applied to the back
side of the substrate, which replaces the backdust material.
SUMMARY OF THE INVENTION
[0005] A roofing shingle is a composite sheet which includes a
roofing substrate having a front side and a back side. An asphalt
material impregnates the substrate and coats at least the front
side of the substrate. A polymer film is attached to the back side
of the substrate and forms a back surface of the roofing shingle.
The polymer film is applied to the substrate in the form of a film.
The roofing shingle does not include backdust on the back surface.
The composite sheet is formed into the size and shape of the
roofing shingle.
[0006] A method of manufacturing roofing shingles includes
continuously supplying a roofing substrate having a front side and
a back side. An asphalt material is applied to the substrate so
that it impregnates the substrate and coats at least the front side
of the substrate. A composite sheet is produced by providing a
polymer film and attaching the polymer film to the back side of the
substrate in a manner that avoids applying backdust to the
substrate so that the polymer film forms a back surface of the
composite sheet. The composite sheet is cut into roofing shingles
while maintaining the back surface free of backdust.
[0007] Various additional aspects of the roofing shingles and their
manufacture will become apparent to those skilled in the art from
the following detailed description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic elevational view, partially in cross
section, of a portion of an apparatus for making roofing shingles
according to the invention.
[0009] FIG. 2 is a schematic plan view of a portion of an
asphalt-coated sheet, showing a roofing shingle made according to
the invention.
[0010] FIG. 3 is an enlarged schematic cross-sectional elevational
view of a first embodiment of a roofing shingle according to the
invention.
[0011] FIG. 4 is an enlarged schematic cross-sectional elevational
view of a second embodiment of a roofing shingle according to the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The present invention relates to roofing shingles in which a
polymer film is attached to the back side of the shingles as a
replacement for the backdust typically used on shingles. The
roofing shingles will be described in more detail below, after a
description of an example of a method of making the shingles.
[0013] Referring now to the drawings, there is shown in FIG. 1 an
apparatus 10 for manufacturing asphalt-based roofing shingles
according to the invention. The illustrated manufacturing process
involves passing a continuous sheet in a machine direction
(indicated by an arrow 12) through a series of manufacturing
operations. The sheet usually moves at a speed from about 300
feet/minute to about 800 feet/minute, but other speeds can be
used.
[0014] In a first step of the manufacturing process, a continuous
sheet of shingle mat 14 is payed out from a roll (not shown). The
shingle mat 14 can be any type of substrate suitable for use in
reinforcing asphalt-based roofing shingles, such as a web, scrim or
felt of synthetic or natural fibrous materials. The fibrous
materials may include, for example, glass fibers, other mineral
fibers, polymer fibers, carbon fibers, cellulose fibers, rag
fibers, or mixtures of these fibers. Suitable mineral fibers may
include fibers of a heat-softenable mineral material, such as
glass, ceramic, rock, slag, or basalt. In one embodiment, the
shingle mat is a nonwoven web of glass fibers.
[0015] The shingle mat 14 is fed, in machine direction 12, through
a coater 16 where a coating of asphalt material 18 is applied to
the shingle mat 14. The asphalt material 18 can include any
materials suitable for coating asphalt-based roofing shingles. The
asphalt material 18 includes asphalt, by which is meant any type of
bituminous material suitable for coating roofing shingles, such as
asphalt, tar or pitch, or any compatible mixture of different
materials. The asphalt material usually includes at least about 20%
asphalt by weight, and often at least about 40%. The asphalt
material can also include various additives and/or modifiers, such
as inorganic fillers or mineral stabilizers. In a typical asphalt
roofing shingle, the coating material includes asphalt and a filler
of finely ground inorganic particulate matter, such as ground
limestone, dolomite or silica, in an amount of from about 40% to
about 80% by weight of the asphalt material. The asphalt material
can also be modified with any suitable polymeric material, which
can be virgin polymers or recycled polymers, to make a polymer
modified asphalt. The asphalt material can also be treated in any
suitable manner with any suitable materials, such as ferric
chloride treated or phosphoric acid treated. The asphalt material
can have any suitable physical properties. In one embodiment, the
asphalt material has a softening point in a range from about
190.degree. F. to about 300.degree. F., but in other embodiments
the softening point can be higher or lower.
[0016] The asphalt coating 18 can be applied in any suitable
manner. In the illustrated embodiment, the shingle mat 14 contacts
a supply of hot, melted asphalt material 18 from a coater 16 to
coat the shingle mat 14 with a tacky coating of asphalt material
18. However, in other embodiments, the asphalt coating 18 could be
sprayed on, rolled on, or applied to the shingle mat 14 by other
means. For example, the asphalt coating could be formed into an
emulsion or a cutback and be cold applied. The asphalt material
impregnates the shingle mat and coats at least the front side of
the mat. The "front side" is the side of the mat facing away from
the roof when the roofing shingle is installed on a roof, and the
"back side" is the side of the mat facing toward the roof.
[0017] In one embodiment, the asphalt material impregnates the
shingle mat and coats the front side of the mat, but it does not
coat the back side of the mat. In another embodiment, the asphalt
material impregnates the shingle mat and coats both the front and
back sides of the mat. The coating apparatus can include any
suitable equipment to control the amount of coating on the back
side of the mat. For example, the equipment can include a scraper
(not shown) or similar apparatus, and/or one or more rolls (not
shown), to remove coating from the back side of the mat in a
controlled manner. The structure of the roofing mat, including the
coating, is further described below.
[0018] The shingle mat 14 exits the coater 16 as an asphalt-coated
sheet 20. The asphalt coating 18 on the asphalt-coated sheet 20
remains hot.
[0019] The asphalt-coated sheet 20 is shown in more detail in FIG.
2. As shown, the asphalt-coated sheet 20 for the three-wide
apparatus 10 comprises six distinct regions or lanes including
three headlap lanes h1, h2, and h3, and three prime lanes p1, p2,
and p3. An exemplary roofing shingle is shown by a phantom line 22
and may be cut from asphalt-coated sheet 20 as shown. In this
manner, three roofing shingles of any length desired may be cut
from each such section of asphalt-coated sheet 20. Each shingle 22
would contain one headlap lane h1, h2, or h3, and one respective
adjacent prime lane p1, p2, or p3. Accordingly, the shingle 22
includes a headlap region 26 and a prime region 24.
[0020] The headlap region 26 of the shingle 22 is that portion
which is covered by adjacent shingles when the shingle 22 is
ultimately installed upon a roof. The prime region 24 of the
shingle 22 is that portion which remains exposed when the shingle
22 is ultimately installed upon a roof.
[0021] In this embodiment, the shingle 22 is cut from the
asphalt-coated sheet 20 to be three feet long by one foot wide. As
further shown in FIG. 2, the shingle 22 includes two cut-out
regions 28 which define three tabs 30. It will be apparent to one
skilled in the art that the asphalt-coated sheet 20 may be
manufactured having a wide variety of widths to allow different
numbers of shingles to be cut therefrom. For example, some roofing
shingle manufacturing plants use an asphalt-coated sheet (not
shown) which is sufficiently wide to allow four, one foot wide
shingles to be cut therefrom. Such a wider asphalt-coated sheet
would include an additional headlap region, and an additional prime
region. Other manufacturing plants use an asphalt-coated sheet (not
shown) which is sufficiently wide to allow six, one foot wide
shingles to be cut therefrom. One skilled in the art will also
recognize that roofing shingles of different sizes, i.e. roofing
shingles having different lengths and/or widths, may be cut from
the asphalt-coated sheet 20. Instead of three-tab roofing shingles
as shown in FIG. 2, alternatively the shingle manufacturing
apparatus can be set up for manufacturing laminated roofing
shingles (not shown) or any other types of asphalt-based shingles.
The manufacture of laminated shingles typically includes adhering
the backs of one section of asphalt-coated sheet to the tops of
another section.
[0022] As further illustrated in FIG. 1, a polymer film 72 is fed
from a roll 74 onto the back side 21 of the asphalt-coated sheet 20
after it exits the coater 16. Another roll 75 presses the film
against the sheet. The hot asphalt coating 18 on the sheet can help
the film to adhere to the sheet. The polymer film 72 is described
in more detail below. Although the embodiment shown in FIG. 1
illustrates one example of a method of applying the polymer film to
the back side of the sheet, it should be recognized that the
polymer film can be applied by any suitable method. Also, the
polymer film can be applied at any suitable location during the
manufacturing process. For example, it could be applied after the
roofing granules are applied as described below.
[0023] As further illustrated in FIG. 1, the asphalt-coated sheet
20 is passed beneath a series of granule applicators 56 and 58 for
applying prime and headlap granules onto the coated sheet. The
granule applicators can be of any type of applicator, blender or
dispenser suitable for applying granules onto the coated sheet,
such as for example a fluted roll applicator, gravity feed
applicator or an auger-type dispenser. An example of a granule
applicator, 56 and 58, is a granule applicator of the type
disclosed in U.S. Pat. No. 5,599,581 to Burton et al., which is
hereby incorporated by reference, in its entirety. Additionally, a
granule valve such as the granule valve disclosed in U.S. Pat. No.
6,610,147 to Aschenbeck may also be used. U.S. Pat. No. 6,610,147
to Aschenbeck is also incorporated by reference in its entirety. In
the embodiment shown, the prime granule applicator 56 is fed from a
prime granule hopper 60 via a prime granule hose 60a. The headlap
applicator 58 can be fed by similar apparatus (not shown).
[0024] Although two granule applicators 56 and 58 are shown in the
embodiment illustrated in FIG. 1, any suitable number and
configuration of granule applicators can be used. For example, a
series of two prime granule applicators can be used, wherein the
granule applicator 56 can be used to apply prime granules 57 onto
the prime lanes p1, p2 and p3 as shown in FIG. 2. Similarly, the
granule applicator 58 can be used to apply headlap granules 59 on
the headlap lanes h1, h2 and h3 as shown in FIG. 2. Applying prime
granules 57 and headlap granules to the coated sheet 20 defines a
granule-covered sheet 62. In another embodiment (not shown),
additional granule applicators can be used for additional granule
drops, such as different colors, sharp demarcations and background
granules.
[0025] As shown in FIG. 1, after all the granules are deposited on
the asphalt-coated sheet 20, the granule-covered sheet 62 is turned
around a slate drum 64 to press the prime granules 57 and headlap
granules 59 into the asphalt coating 18. The slate drum 64
temporarily inverts the granule-covered sheet 62 so that the excess
and non-adhering granules fall off. The excess granules fall into a
backfall container 70 and are recovered for later use. The granule
covered sheet is turned around a drum 78. The granule-covered sheet
62 is passed between a pair of press rolls 80, 82 that further
press the prime granules 57 and headlap granules 59 into the
granule-covered sheet 62.
[0026] As further shown in FIG. 1, downstream from the press rolls,
80 and 82, the granule covered-sheet 62 is passed through a cooling
section 84. The cooling section 84 is configured to sufficiently
cool the granule-covered sheet 62 to allow downstream manufacturing
operations. In one embodiment, the cooling section 84 includes
rollers allowing the granule-covered sheet 62 to be passed up and
down while being sprayed with water to cool the hot asphalt coating
18. In another embodiment, any means of cooling the granule-covered
sheet 62 can be used. A laminated roofing shingle has additional
process steps.
[0027] Downstream from the cooling section 84, the granule-covered
sheet 62 is subsequently fed through a cutter 86 that cuts the
granule-covered sheet 62 into individual shingles 22. The cutter 86
may be any type of cutter, such as for example a rotary cutter,
sufficient to cut the granule-covered sheet 62 into individual
shingles 22.
[0028] FIG. 3 shows a cross-section, taken through the prime
region, of a first embodiment of a roofing shingle 22 according to
the invention. The roofing shingle 22 includes a roofing mat 14 or
substrate. The roofing mat 14 has a front side 14f and a back side
14b. An asphalt material 18 impregnates the roofing mat 14 and
coats the front side 14f of the mat. In the embodiment shown in
FIG. 3, the asphalt material 18 does not coat the back side 14b of
the mat. However, FIG. 4 (described below) shows an embodiment in
which the asphalt material coats both the front side and the back
side of the mat. Prime granules 57 are embedded in the front
surface of the asphalt material 18.
[0029] A polymer film 72 is attached to the back side of the
roofing mat and forms a back surface of the roofing shingle 22. The
polymer film replaces the backdust typically included on roofing
shingles. The polymer film can be made from any suitable
material(s), and it can have any suitable structure and properties.
By "film" is meant a substantially continuous sheet of polymer, in
contrast to discontinuous structures such as woven or nonwoven
sheets or webs.
[0030] The polymer film 72 can be attached to the back side of the
roofing mat by any suitable method. For example, the surface of the
film can be heated (not shown) to make it soft so that it adheres
to the mat during production of the shingle. Alternatively, the
polymer film can be a self-adhering film similar to Scotch brand
adhesive tape. Alternatively, any suitable adhesive (not shown) can
be used for adhering the polymer film to the roofing mat during
production of the shingle.
[0031] The polymer film can be produced from any suitable polymer
or any suitable blend of different polymers. Some examples of
polymers that may be used to produce the polymer film include
polyolefins such as polypropylene and polyethylene; or polyesters
such as polyethylene terephthalate, polyethylene naphthalate or
polybutylene terephthalate. Either low density or high density
polyolefins could be used. In some embodiments, a polymer such as a
polyamide, for example nylon, can be blended with the polyolefin or
polyester to control the melt temperature or other properties of
the film. Also, in some embodiments, the polymer excludes materials
such as polyvinyl chloride, polycarbonate, ionomer resin and
polyvinylidene chloride. In contrast to the roofing shingles
disclosed in U.S. 2007/0218250 A1, the film is not a hot melt
material.
[0032] The polymer film can include conventional additives such as
antioxidants, delusterants, pigments, fillers such as silica,
calcium carbonate, kaolin, titanium dioxide, antistatic agents and
the like, or mixtures thereof.
[0033] The polymer film can be produced by any suitable method,
such as any of those known in the art. In one method of making a
relatively high strength polymer film, the polymer is melted and
extruded as an amorphous sheet onto a revolving casting drum to
form a cast sheet of the polymer. The sheet is cooled and then
stretch oriented in one or more directions to impart strength and
toughness to the film. Where necessary, the film is heat treated
after stretching to lock in the properties by further crystallizing
the film.
[0034] The polymer film can have any suitable thickness. Depending
on the type of polymer used, and depending on whether or not the
film is used to strengthen the roofing shingle, the thickness of
the film can vary over a wide range. For example, in some
embodiments the polymer film has a thickness within a range of from
about 0.05 mil to about 35 mils, and more particularly from about
0.3 mil to about 20 mils. In some embodiments the polymer film is a
relatively thin film, for example, having a thickness within a
range of from about 0.05 mil to about 10 mils, and more
particularly from about 0.3 mil to about 6 mils. In other
embodiments the polymer film is a relatively thick film, for
example, having a thickness within a range of from about 10 mils to
about 35 mils.
[0035] Different approaches may be taken in the selection of the
polymer film. In some embodiments, the polymer film is a relatively
high strength film that not only functions as a parting agent like
backdust, but that also builds significant strength properties into
the roofing shingle. For example, the polymer film may have a tear
strength of at least about 1500 g, more particularly at least about
1700 g, and more particularly at least about 2000 g. The tear
strength measurement can be the Elmendorf tear strength measured in
accordance with ASTM Method D1922, although any other suitable
strength measurement can be used. Some examples of relatively high
strength films include oriented polyethylene or polypropylene
films, or films made from a blend of polyethylene or polypropylene
with a high strength polymer such as nylon.
[0036] The use of a relatively high strength film could enable the
production of a higher strength roofing shingle, or it could enable
the production of a roofing shingle having the same strength but
including a lower strength roofing mat. In one embodiment, the
roofing mat is a relatively lightweight mat weighing not more than
about 1.6 lb/100 ft.sup.2, and the polymer film has sufficient
strength to maintain the strength of the roofing shingle with the
lightweight mat. For example, a current roofing shingle having
sufficient strength may include a roofing mat having a weight of
1.95 lb/100 ft.sup.2, but a roofing shingle made with a polymer
film may be able to use a roofing mat having a weight of 1.3-1.5
lb/100 ft.sup.2 while obtaining the same shingle strength.
[0037] In other embodiments, the polymer film is a relatively low
strength film that functions as a parting agent like backdust but
that does not provide any significant strength to the roofing
shingle. For example, the polymer film may have a strength of less
than about 1000 g, more particularly less than about 500 g, and
more particularly less than about 100 g. Some examples of
relatively low strength polymer films include non-oriented polymer
films, films made from recycled polymers, and/or very thin films.
For example, the polyethylene films used to produce garbage bags
are usually relatively thin and low strength films.
[0038] FIG. 4 shows a cross-section, taken through the prime
region, of a second embodiment of a roofing shingle 23 according to
the invention. The roofing shingle 23 includes a roofing mat 14 or
substrate. The roofing mat 14 has a front side 14f and a back side
14b. An asphalt material 18 impregnates the roofing mat 14 and
coats the front side 14f of the mat. Prime granules 57 are embedded
in the front surface of the asphalt material 18. A layer 19 of the
asphalt material 18 also coats the back side 14b of the mat. A
polymer film 72 is attached to the back side of the layer 19 of
asphalt material and forms a back surface of the roofing shingle
23. In one embodiment, the layer 19 of asphalt material 18 is a
relatively thin layer that is just thick enough to act as an
adhesive, when molten during the production of the shingle, to bond
the polymer film 72 to the roofing mat 14. For example, a
relatively thin layer 19 of asphalt material 18 may have a
thickness within a range of from about 0.5 mils to about 5 mils.
Optionally, the asphalt material 18 or the polymer film 72 can be
modified in any suitable manner to facilitate the bonding and/or to
increase the strength of the bond. In another embodiment, the layer
19 of asphalt material 18 may have a wider thickness range, for
example, a thickness within a range of from about 1 mil to about 20
mils, and more particularly from about 3 mils to about 9 mils.
[0039] The principle and mode of operation of this invention have
been described in its preferred embodiments. However, it should be
noted that this invention may be practiced otherwise than as
specifically illustrated and described without departing from its
scope.
* * * * *