U.S. patent number 3,815,285 [Application Number 05/249,848] was granted by the patent office on 1974-06-11 for covered window sash and method for making the same.
This patent grant is currently assigned to Rolscreen Company. Invention is credited to Herman S. Kuyper.
United States Patent |
3,815,285 |
Kuyper |
June 11, 1974 |
COVERED WINDOW SASH AND METHOD FOR MAKING THE SAME
Abstract
A clad or covered window sash and a method for making the same.
Aluminum panels are permanently mounted so as to cover the exterior
portions of a wood window sash. The aluminum panels are coextensive
with the rails and stiles which define the sash. The panels include
hook portions on both of their outer edges which engage with edge
portions provided on both the inner and outer peripheries of the
wooden sashes and stiles. The metal panels are secured to each of
the rails and stiles of an assembled wooden sash without any
fasteners and they are snapped into position over the exterior
portion of each of the stiles and rails.
Inventors: |
Kuyper; Herman S. (Knoxville,
IA) |
Assignee: |
Rolscreen Company (Pella,
IA)
|
Family
ID: |
22945267 |
Appl.
No.: |
05/249,848 |
Filed: |
May 3, 1972 |
Current U.S.
Class: |
49/501; 49/504;
52/656.6; 52/717.01 |
Current CPC
Class: |
E06B
3/302 (20130101) |
Current International
Class: |
E06B
3/30 (20060101); E06b 003/00 () |
Field of
Search: |
;49/501,504,DIG.1
;52/716,727 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
877,294 |
|
Sep 1961 |
|
GB |
|
943,963 |
|
Dec 1963 |
|
GB |
|
Primary Examiner: Downey; Kenneth
Attorney, Agent or Firm: Molinare, Allegretti, Newitt &
Witcoff
Claims
What I claim and desire to secure by Letters Patent is:
1. A window sash comprising, in combination, upright and elongated
spaced wood stiles interconnected by top and bottom spaced and
elongated wood rails, an exterior portion on each of said rails and
stiles, a continuous inwardly directed rabbet defined by said
interconnected rails and stiles, window glass received within said
rabbet, means positioned within said rabbet for providing a weather
seal between said rails and stiles and said window glass, said
exterior portions of said stiles and rails having a continuous
inner edge portion defining an outer wall for said continuous
rabbet, a continuous inner peripheral portion defined on said inner
edge portion, a continuous outer peripheral portion spaced
outwardly from said inner peripheral portion defined on said
exterior portion, a plurality of elongated, flexible, metallic
panels mounted over and adjacent each of said exterior stile and
rail portions and defining a continuous protective covering for
said exterior stile and rail portions, the ends of adjacent panels
being in substantial overlapping relationship, weather seal means
defined at said overlapping ends, each of said panels having inner
and outer edge portions, longitudinal hook means defined on said
inner and outer edge portions, said inner and outer hook means
cooperating with both said inner and outer peripheral portions,
respectively, for defining the sole means for securing said panels
to said stiles and rails, said longitudinal hook means on said
inner edge portions cooperating with said weather seal means to
define a seal therewith, said hook means and said peripheral
portions being constructed and arranged to have said hook means
pass over said peripheral portions of said stiles and rails in a
direction transverse to the length of said elongated stiles and
rails and into permanent securing relationship with said peripheral
portions of said stiles and rails, thereby defining said sole
securing means therebetween.
2. The article of claim 1 wherein said window sash is a double hung
window sash.
3. The article of claim 1 wherein said window sash is a casement
window sash.
4. The article of claim 1 wherein said window sash is a sliding
glass door.
5. The article of claim 1 wherein said panels are roll-formed
aluminum.
6. The article of claim 1 wherein said weather seal means includes
the protective panel at said top rail of said sash overlapping the
upper ends of the protective panels covering said upright stiles,
and the lower ends of said stile covering panels overlapping the
lateral ends of said panel covering said bottom rail.
7. The article of claim 1 wherein said weather seal means includes
a sealing material positioned between said sash and the overlapping
ends of said panels.
8. In a window sash of the type which includes spaced, upright and
elongated wood stiles interconnected by top and bottom spaced and
elongated wood rails, an exterior portion on each of said stiles
and rails, a continuous inwardly facing rabbet defined by said
interconnected rails and stiles, window glass fixedly received
within said rabbet, means positioned in said rabbet for providing a
weather seal between said rails and stiles and said window glass,
said exterior portions of said stiles and rails having a continuous
inner edge portion defining an outer wall for said continuous
rabbet, the improvement comprising a continuous inner peripheral
portion defined on said inner edge portion, a continuous outer
peripheral portion spaced ouwardly from said inner peripheral
portion defined on said exterior portion, a plurality of elongated,
flexible, metallic panels mounted over and adjacent each of said
exterior stile and rail portions for defining a continuous
protective covering for said exterior stile and rail portions, the
ends of adjacent panels being in substantial overlapping
relationship, each of said panels having inner and outer edge
portions, longitudinal hook means defined on said inner and outer
edge portions, said inner and outer hook means cooperating with
said inner and outer peripheral portions, respectively, for
defining the sole means for securing said panels to said stiles and
rails, said inner longitudinal hook means cooperating with said
weather seal means to define a weather seal therewith, said hook
means and said peripheral portions being constructed and arranged
to have said hook means pass over said peripheral portions of said
stiles and rails in a direction transverse to the length of said
stiles and rails and into permanent securing relationship with said
peripheral portions of said stiles and rails, thereby defining said
sole securing means therebetween.
9. The article of claim 8 wherein said panels are roll-formed
aluminum.
10. The article of claim 8 wherein said weather seal means includes
sealing materials provided between said sash and said panels where
said ends of said panels are in said overlapping relationship.
11. The article of claim 8 wherein said weather seal means includes
the protective panel for said top rail overlapping the upper ends
of the protective panels covering said upright stiles, and the
lower ends of said stile covering panels overlapping the lateral
ends of said panel covering said bottom rail.
Description
BACKGROUND OF THE INVENTION FIELD OF THE INVENTION and DESCRIPTION
OF THE PRIOR ART
This invention relates to an improved window construction and it
particularly relates to a wooden sash which has its exterior
portion, normally exposed to the weather, covered by protective
metal cladding and it also relates to a method for constructing
such metal clad wooden window sash.
Windows, both sashes and frames, are commonly constructed entirely
of wood. It is also common to construct both sashes and frames
entirely of metal, principally aluminum. One of the principal
reasons why metal frames and sashes are selected over wooden frames
and sashes is the significant reduction in time and expense
required for the external maintenance of metal, as opposed to wood
windows. This is particularly true in the case of large office and
commercial buildings, wherein the external maintenance expenses are
desirably kept at a minimum. At the same time, one of the principal
reasons why wood windows are not selected for use over all - metal
windows is that normal good maintenance requires painting of the
exposed wood every few years. As a result, in large commercial
buildings, the periodic painting needed for wood windows is
sometimes considered undesireably expensive.
On the other hand, wood frames and sashes are selected over metal
windows when the internal appearance of the windows is of primary
concern. Generally, the internal appearance of a wood window is
considered superior to that of an all metal window. For example,
from the standpoint of appearance and beauty, particularly
interior, when wood windows are stained or painted, their inside
appearance is far more pleasing than that of metal windows. Also,
even if metal windows are painted, there is generally an adhering
problem and peeling and chipping of the paint from the metal is
quite common. If all-metal windows are not painted, their internal
appearance is generally not as visually pleasing as a properly
stained or painted wood window.
In addition to the appearance advantage that wood windows have over
metal windows, there is a significant functional advantage of wood
windows over metal windows. This advantage is particularly apparent
in cold climates where the significantly better insulating
qualities of wood are apparent in comparison to the relatively poor
insulating qualities of the all-metal windows. The poor insulating
qualities of metal have the disadvantage of resulting in a heating
loss in the cold months and a cooling loss in the summer. Also, in
cold climates, condensation and frost often develop along the metal
frames and sashes, even if insulating glass panels are used. Such
condensation development creates an unsightly appearance, as well
as maintenance and cleaning problems.
From the above, it is seen that the principal disadvantage of wood
windows over metal windows may be overcome by applying a permanent
covering of some type over the exterior portion of the wood windows
that are subject to weather conditions. The two materials that come
to mind for this purpose are plastic and metal. Plastic cover
panels have the disadvantage of having a limited life since
plastics known to be useful for such a purpose are subject to
sunlight and oxygen deterioration after a period of years.
As a result of the foregoing, it is considered desirable to cover
the exterior wood portions of the window frame and window sash with
metal, preferably aluminum. As far as the frame iteself is
concerned, it has been known to construct extruded aluminum sills,
jambs, and heads which are interconnected to interior wood
portions. The use of heavy extruded aluminum members for the sash
portion of the window is considered undesireable from a material
cost standpoint. Also, assembly would be costly as it would
probably be necessary to slide the cladding on the stiles and rails
and it would probably not be possible to assemble the matal
cladding or covering over a fully assembled sash. By having a
design which permits assembly of the cladding to an assembled sash,
the sash could be selectively covered with metal cladding or could
be used without cladding, thereby permitting the use of one
assembly line to make sashes, regardless if some of the assembled
sashes are ultimately clad. Also, in assembling the metal panels to
the wood sash, consideration should be given to maintaining
assembly costs at a minimum while retaining a desireable external
appearance. Thus, external fasteners, which not only create
appearance problems but which also add labor and material costs,
are to be avoided.
SUMMARY OF THE INVENTION
It is therefore an important object of this invention to provide an
improved window sash and a method for making the same wherein the
window sashes are primarily constructed of wood and are covered or
clad by an exterior protective metal panel.
It is also an object of this invention to provide an improved clad
or covered window sash assembly wherein the disadvantages of prior
art constructions are substantially avoided.
It is another object of this invention to provide an improved metal
clad wood window and method for making the same wherein metal
panels are assembled to the sash without the use of fasteners and
following complete assembly of the wood sash.
It is a further object of this invention to provide an improved
clad window sash wherein cooperating elements are provided on the
wood sash and on the metal clad panels for fixedly holding the
panels to the sash without external fasteners.
It is still another object of this invention to provide a metal
clad window sash and method for making the same wherein the product
and method are particularly characterized by their simplicity and
economy of construction, manufacture, and assembly.
It is also a further object of this invention to provide a metal
clad window sash wherein the metal panels are snapped directly in
place over the wood stiles and rails of the sash without the use of
any fasteners and following the complete assembly of the wood sash
including a suitable glazing panel.
It is yet another object of this invention to provide an improved
metal clad window sash wherein the construction and method for
making the same may be used in conjunction with a variety of window
products, including double-hung windows, casement windows, and
sliding glass doors.
It is also another object of this invention to provide a metal clad
window sash wherein the metal cladding includes portions which have
a dual function of engaging the wood stiles and rails of the sash
for securement thereto and of sealably biting into the sealing
material located between the glazing panel and the window
frame.
Further purposes and objects of this invention will appear as the
specification proceeds.
The foregoing objects are accomplished by providing a wood window
sash which includes upright spaced stiles interconnected by spaced
top and bottom rails, an exterior portion being included on each of
the rails and stiles, a metal panel being permanently mounted
adjacent to the exterior side of each of said rails and stiles, and
cooperating means, including hook portions on said panels and edge
portions on said exterior portions of said stiles and rails, for
securing said panels in place on a pre-assembled sash, said
cooperating means being devoid of other fastener means.
BRIEF DESCRIPTION OF THE DRAWINGS
Particular embodiments of the present invention are illustrated in
the accompanying drawings wherein:
FIG. 1 is a pictorial, partially broken view of my improved metal
clad window sash used in conjunction with a casement type
window;
FIG. 2 is a partially broken, pictorial view, of a double hung
window wherein my improved metal clad window sash construction is
used;
FIG. 3 is a partially broken, pictorial view, of my improved metal
clad sash construction used in conjunction with sliding glass
doors;
FIG. 4 is a pictorial view, in section, of a typical metal panel
prior to assembly to a window sash;
FIG. 5 is an enlarged cross-sectional view of a metal cladding
panel, as it is being assembled, in one manner, to a preassembled
window sash;
FIG. 6 is a view similar to FIG. 5, except the metal cladding panel
is shown as it is being assembled, in another manner, to a
preassembled window sash;
FIG. 7 is a cross-sectional view of a typical metal panel assembled
in place to a window sash; and
FIG. 8 is a broken, partially sectioned front view of a corner of a
metal cladding panel assembled in place over the exterior of a
window sash.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 - 3, my improved clad window, generally 10, is
shown as used as a casement window (FIG. 1), generally 12, on a
double hung window (FIG. 2), generally 14, and on a sliding glass
door assembly (FIG. 3), generally 16.
Referring first to FIG. 1, clad window sash 10 is shown on the
casement window 12. Although the window frame 18 in FIG. 1 is shown
constructed from wood, it is to be understood that it is preferable
for not only the window sash 12 to be clad, but also for the window
frame 18 to be clad so that all the advantages of my invention can
be better realized. The embodiment of FIG. 1, however, does show
that the window sill 20, the head 22, and the window jambs 24, may,
if desired, be made of wood while the sash can be clad. Also, for
convenience of illustration, the mechanical parts of the window 12,
such as window cranks, and the like, have not been shown in the
embodiment of FIG. 1 as well as the other embodiments shown. In the
embodiment of FIG. 1, only the casement window sash 26 has
protective cladding panels 28, 30, and 32 covering the wood upper
rail 34, stiles 36, and bottom rail 38. In the casement window 12,
an outer glazing panel 40 is received in a continuous rabbet 42
provided in the inner perimeter of the sash 26, and a wood glass
stop 44 is cemented along the inner rim of the sash 26 to hold the
glazing panel 40 in place. In the window 12, a double glazing panel
46, removable from the room interior, is mounted in the window 12
so as to provide an air space for insulation between the panels 40
and 46.
In the embodiment of FIG. 1, the panels 28, 30 and 32 are
preferably made of rolled, formed aluminum, as about .024 inches
thick, and are assembled directly to a fully assembled sash 26
having the glazing panel 40 therein. In assembling the protective
cladding panels 28, 30 and 32 to the sash 26, the bottom panel 32
is first mounted on or secured to the bottom rail 38. The stile
panels 30 are then assembled over the stiles 36, in order that the
lower ends of the stile panels 30 overlap the lateral outer edges
of the bottom rail panel 32. After installing the stile panels 30,
the top protective panel 28 is placed over the top rail 32 so as to
overlap the upper ends of the stile panels 30. By incorporating a
method of installing the cladding panels over the assembled sash
26, in this manner, lap joints 48, or overlapping beveled or
mitered ends, assist in providing a weather or moisture seal to
avoid moisture forming between the metal cladding panels 28, 30 and
32, and the rails 34 and 38 and stiles 36. Such weather seal
results since the lateral beveled ends of the top rail panel 28
overlap the beveled upper ends of the stile panels 30, causing rain
water to pass or flow over the lap joint 48. Similarly, the rain
water or moisture dripping down the stile panel 30 flows over
bottom lap joints 48. As will be described hereinafter in greater
detail, a sealant is also provided at each of the lap joints
48.
Referring to the embodiment of FIG. 2, the protective cladding is
used on the double hung window 14. In the embodiment of FIG. 2, the
window sill 50, the head 52, and the window jambs 54, all have an
exterior protective cover of extruded aluminum. As shown, the sill
extrusion 56 is interconnected to an interior wood sill portion 58.
Similarly, the jamb extrusions 60 are secured to wood jamb portions
(not shown). A head extrusion 62 is interconnected to the interior
wood portion of the head 52 of the window 14. The head 52, like the
sill, 50, and jambs, retains the interior appearance of wood while
the window frame has an exterior metal of the desired color, as a
coating of a high temperature baked acrylic polymer.
The upper sash 64 of the double hung window 14 has a protective
panel 66 secured to the top rail 68, a protective panel 70 secured
to each of the upright stiles and a clad panel 72 is secured to the
bottom rail 74. As in the embodiment of FIG. 1, the bottom panel 72
is installed first to the bottom rail 74, then the stile panels 70
are mounted on the stiles so as to define a lap joint 76 at each of
the bottom corners, and finally the upper protective panel 68 is
mounted in place so as to provide the desired lap joints 76 at the
upper corners.
The bottom protective panel 72 on the bottom rail 74 has a somewhat
different cross-sectional shape from the protective panels 66 and
68 used on the top rail 68 and on the stiles. As seen in FIG. 2,
the bottom panel 72 has an outer stepped portion which receives the
frame of a window screen (not shown). Also, a planar bottom portion
80 extends across the entire lower surface of the bottom rail 74 so
as to cover the entire surface and protect it from exposure to
weather conditions.
The lower sash 82 has a protective panel 84 covering the top rail
86, stile panels 88 covering the exterior surfaces of the stiles
and a bottom panel 90 covering the bottom rail 92. As in the
embodiment of FIG. 1 and as in the case of the upper sash 64 of the
embodiment of FIG. 2, the bottom panel 92 is installed first and
then the stile panels 88 are installed to provide the appropriate
lap joints 94 at the lower corners; finally, the top panel 84 is
installed over the beveled upper ends of the stile panels 88 in
order to provide the desired lap joints 94 at the upper corners. In
the lower sash 82 of the embodiment of FIG. 2, the top panel 84 has
a somewhat different cross-sectional shape than the panels 88 and
90. This difference results from the requirement that the top check
rail 86 is to have an interior appearance of wood. A continuous lip
96 is received within a groove provided in the exterior face of the
top rail 86. A weatherstrip seal 97 is positioned on the inner face
of the bottom check rail 74 and, in the closed position, bears
against the outer, upright face of the top protective panel 84 of
the lower sash 82.
As in the embodiment of FIG. 1, the lap joints 94 and the lap
joints 76 preferably have associated therewith a sealing mastic or
material which will be hereinafter discussed in greater detail.
Referring to the embodiment of FIG. 3, my clad window design is
shown used with the sliding glass door construction 16. As in the
embodiment of FIG. 2, the embodiment of FIG. 3 has a window frame
98 which is constructed on its exterior of extruded aluminum. An
extruded aluminum sill 100 is provided on the exterior and is
interconnected to a wooden portion of the sill which is located on
the interior only. Similarly, an extruded aluminum jamb 102 and an
extruded aluminum head 104 are rigidly interconnected to the wood
portions of the jamb and head. Each door 106 is constructed in
substantially the same manner, it being understood that one of the
doors 106 is fixed while the other is moving. In both cases, the
doors 106 include double glazing panels 108 for thermal insulation
purposes. The bottom rail 110 is covered by a protective panel 112,
the stiles of the doors 106 are covered by protective panels 114,
and the top rail 116 of each door 106 is covered by a top
protective panel 118. As in the embodiment of FIGS. 1 and 2, the
lower panel 112 is installed on the assembled door 106 first, then
the stile panels 114 are installed so as to overlap the bottom
panel 112 and provide suitable lap joints 120 at the bottom
corners; finally, the top panel 118 is installed so as to overlap
the beveled upper ends of the stile panels 114 so as to provide the
lap joints 120 at the upper corners of the door 106. Again, for
convenience of illustration, the hardware used on the sliding doors
106 is not shown, as such details form no part of this
invention.
Referring to FIG. 4, there is shown a typical enlarged pictorial
view, in section, of a typical panel section of the type used in
the embodiments of FIGS. 1 - 3. The only places of the embodiments
of FIGS. 1 - 3 which do not use the design shown in FIG. 4 are the
panels 72 and 84 on the check rails 74 and 86 of the double hung
window 14 of FIG. 2. In the panel embodiment of FIG. 4, the panel,
generally 122 includes a generally upright planar portion 124 which
is positioned exterior and adjacent the vertical outer faces of the
stiles and rails which define the sashes in the embodiments of
FIGS. 1 - 3. The portions of the assembled panels 122 define an
outer and inner perimeter. Each outer perimeter section of each
panel has a rearwardly extending section 126 which terminates with
an outwardly directed hook portion 128. Each section 126 extends at
substantially a right angle to the planar portion 124. Each inner
perimeter section of the panels 122 includes an upwardly and
inwardly angled section 130 which terminates with an inturned hook
132. Preferably, each panel is constructed of roll-formed aluminum
having a thickness of about 0.024 inches. Although material other
than metal, such as extruded plastic, could be used to form the
panel 122, metal, as aluminum, is preferably used because of the
ability of the aluminum to withstand adverse weather conditions and
sunlight. Furthermore, in view of the method of assembling the
panels to the assembled sash, it is impoatant that the material
used for the panels has sufficient resiliency, without the danger
of breakage; an aluminum panel has been found to have these desired
qualities.
With respect to the check rail panels 72 and 84, their structures
are different from each other and from the conventional cladding or
panels. The panel 72 on the upper sash 64 has a hook 132 and an
angle section 130, as with the panel 122, shown in FIG. 4. The
panel 72 also has a planar portion 124, as with the panel 122. The
bottom portion 162 of the panel 72, as previously described extends
across the entire bottom of the bottom rail 74 and has the stepped
portion 164 to receive a screen (not shown). An upturned continuous
lip 166 is received by the rear, lower corner of the bottom rail
184. As to the check rail 86 in the lower sash 82, the panel 84
includes the hook 132 and angled section 130. The panel 84,
however, has a front portion 168 which terminates in the continuous
lip received in the front or exterior face of the check rail
86.
Referring to FIGS. 5 - 7, one of the important advantages of my
invention is simplicity and ease by which the panels 122, as shown
in FIG. 4, may be assembled directly to an otherwise fully
assembled sash. The panels 122 are constructed so as to be snapped
in place over the interior wood portions of the fully assembled
stiles and rails, without the use of any external fastener
means.
Referring to FIG. 5, one method of assembling the panel 122 to a
rail 134, for example, is shown. In this embodiment the hook
section 128 is first placed into engagement with an inwardly facing
edge or ledge 136 defined along the outer perimeter or periphery of
the jamb 134. The upper hook 132 is then slid or forced along a
slanted surface 138 provided on the inner perimeter of the jamb
134, and the hook 132 is forced around an edge 140 where it engages
the jamb, as best shown in FIG. 7. It is also important for the
downwardly extending hook 132 to sealably bite into the sealing
mastic 142 which may be used to seal the periphery of an insulating
glass panel 144. In this way, a weather-tight seal is provided
between each panel 122 and the inner periphery of the wood sections
of the window sash.
Alternatively, the panel 122, referring to FIG. 6, may be assembled
to the stile or rail 134 by having the upper hook 132 first placed
into engagement with the upper edge 140 and then the other hook 128
is passed over the beveled surface 146 and slid over the outer
exterior portion 148 until the hook 128 engages or snaps over the
ledge 136. It is thus seen that the panel 122 is permanently
installed on the window sash without the use of external fasteners
and after the entire window, including the glass, has been
constructed. A further advantage of the applicant's construction is
that the window sash may be used with or without the metal cladding
since the sash is designed not only to receive the metal cladding,
but, even without the metal cladding, it has substantially the same
external appearance of a normal wood window.
Referring to FIG. 8, an enlarged section of a lap joint 150 such as
that shown in FIGS. 1 - 3 is shown. The lap joint 150, shown is the
type which would be positioned at a lower corner section. The stile
panel 152 has its beveled lower edge overlapping the beveled
lateral edge of the bottom rail panel 154 by a small amount, as 1/8
- 1/4 inch. Prior to placing the bottom rail panel 154 in place, a
strip of mastic as a butyl rubber mastic 156 is laid on the lateral
beveled edge of the panel 154, which edge passes from the inner
corner 158 to the outer corner 160 of the intersecting rail and
stile. After the overlapping panel is placed thereover, the mastic
156 acts as a further weather seal between the panels 122 and the
wooden portions of the sash. All areas of the adjacent metal panels
and wood window portions that are normally exposed to moisture are
thereby provided with a moisture seal. Also, by placing the
protective panels in place on a sash in the manner described to
provide the desired lap joints, there is essentially no build-up of
moisture between the wood sections and the metal panels. Although
there is no sealing mastic between the panels and the window sash
along the edge defined by the hooks 128 and ledges 136, even after
an extended period of exposure to weather, there has been no
moisture build-up found.
From the foregoing description, it is seen that I have provided a
uniquely constructed window sash having a protective panel, as
aluminum, clad or sheathed over a wood window sash. In this way,
the insulating properties of the wood window is preserved while the
exterior is covered with a weather proof metal paneling which is
protected with an enamel having the desired color, resulting in
minimal exterior maintenance problems for the windows. At the same
time, the interior beauty of the wood is preserved. The particular
design does not use additional fasteners and the cladding is
mounted on the windows following complete assembly of the windows
merely by snapping each panel in place over the sections of the
sash.
While in the foregoing, there has been provided a detailed
description of particular embodiments of the present invention, it
is to be understood that all equivalents obvious to those having
skill in the art are to be included within the scope of the
invention as claimed.
* * * * *