U.S. patent number RE34,787 [Application Number 08/094,694] was granted by the patent office on 1994-11-15 for bidirectional gasket having water energizing pockets.
This patent grant is currently assigned to Poly-Tec Products, Inc.. Invention is credited to James A. Kelly, James A. Westhoff.
United States Patent |
RE34,787 |
Westhoff , et al. |
November 15, 1994 |
Bidirectional gasket having water energizing pockets
Abstract
A bidirectional gasket providing a water-tight seal between an
opening in a manhole assembly and a pipe extending into said
opening, comprises a T-shaped anchoring portion for embodiment in a
manhole opening. A substantially A-shaped pipe engagement portion
is joined to the anchoring portion by a slender connecting web
facilitating bending of the gasket. The A-shaped portion has "legs"
and recesses which form water pockets preventing water from
entering. The durometer of the gasket material enhances the
water-tight seal of the legs with increasing water pressure. The
pipe engaging portion accommodates a greater outside pipe diameter
compared with conventional connectors due to reduced volume, by
providing voids within the connector together and a lower durometer
of gasket material. The gasket has enhanced ability to accommodate
diameter deflection or ovation in rigid and flexible pipe
materials. The A-shaped profile allows for greater angular
deflection and/or pipe misalignment compared with conventional
connectors. The gasket apex has a recess to locate the voids which,
in addition to enhancing mechanical softness of the gasket, also
provides the ability to increase gasket compression by introducing
a liquid filler into the voids. Tapered projections near the apex
wipe the external periphery of a pipe upon insertion and also
contribute to the compression of the nose portion of the connector.
The gasket may be molded or formed from an elongated extrusion
joined at its ends to form an annular gasket.
Inventors: |
Westhoff; James A. (Langhorne,
PA), Kelly; James A. (Warrington, PA) |
Assignee: |
Poly-Tec Products, Inc.
(Tullytown, PA)
|
Family
ID: |
25676990 |
Appl.
No.: |
08/094,694 |
Filed: |
July 21, 1993 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
825135 |
Jan 24, 1992 |
05217237 |
Jun 8, 1993 |
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Current U.S.
Class: |
277/605; 277/606;
277/617; 277/626; 285/110; 285/230 |
Current CPC
Class: |
F16L
5/025 (20130101); F16L 5/10 (20130101) |
Current International
Class: |
F16L
5/02 (20060101); F16L 5/10 (20060101); F16J
015/10 () |
Field of
Search: |
;277/27,186,189,27A,181,27R,211,215,226
;285/95,110,345,346,230 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0215745 |
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Jun 1961 |
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AT |
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0090934 |
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Oct 1983 |
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EP |
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1373279 |
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Aug 1964 |
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FR |
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1545368 |
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Nov 1968 |
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FR |
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3803729 |
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Aug 1989 |
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DE |
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Primary Examiner: Cummings; Scott W.
Attorney, Agent or Firm: Weinstein; Louis
Claims
What is claimed is:
1. A bidirectional annular gasket for providing a water-tight seal
between an opening in a barrier wall and a pipe inserted into said
opening, said gasket comprising a ring of elastomeric material
having a substantially uniform cross-section along its
circumferential length, said cross-section comprising a T-shaped
anchoring portion including a radially-outwardly directed foot
portion and a neck portion integral with said foot portion and
extending at right angles and radially inward therefrom to form
said T-shaped anchoring portion and a head portion extending
radially inward of said foot portion for engagement with the
exterior of said pipe;
said head portion having a substantially A-shaped configuration
defined by a wide end tapering to a narrow tip, with the wide end
of said A-shaped configuration being positioned adjacent said
anchoring portion and a narrow tip forming an apex of said head
portion and, prior to insertion of a pipe, extending radially
inwardly from and being remote from said anchoring portion;
the head portion, prior to insertion of a pipe, being substantially
symmetrical about a plane passing through the center of the head
portion and aligned with said radial direction;
the wide end of said head portion being provided with a recess
defining a pair of legs extending diagonally outward and away from
the main body of said head portion;
a connecting web joining said A-shaped configuration and said
anchoring portion and being integrally joined at a first end to the
wide end of said A-shaped configuration substantially at midpoint
of said recess and at a second end to a radially inward end of said
neck portion; and
said connecting web dividing said recess into a pair of pockets on
opposite sides of said web.
2. The gasket of claim 1 wherein the thickness of said connecting
web, measured in a direction perpendicular to said plane, is less
than the thickness of said neck portion measured in said
perpendicular direction to facilitate flexing and bending of said
connecting web upon insertion of a pipe into said gasket when the
diameter of the pipe is greater than the diameter defined by the
apex of said gasket head portion causing said gasket to bend in a
region of said connecting web.
3. The gasket of claim 1 wherein .Iadd.said head portion is
provided with first and second cavities each of substantially
circular cross-section and spaced from one another in a radial
direction to define a wall between said cavities transverse to said
plane, each of said cavities extending substantially continuously
about the circumference of the gasket and said A-shaped portion is
further provided with a recess at the tip of said A-shaped portion
to facilitate location of said cavities and to facilitate insertion
of a hypodermic-type needle for insertion of a liquid material into
at least one of said cavities to alter .[.the.]. compressibility of
the gasket.
4. A bidirectional gasket for use in forming a fluid-tight seal
between a pipe and an opening in a barrier wall through which said
pipe passes, comprising:
an annular member of elastomeric material having a tubular head
portion of a substantially A-shaped cross-section defined by a wide
end and having tapering sides tapering to a narrow tip and a foot
portion comprising a base flange portion and a neck portion of
substantial thickness integrally joined to a mid-region of said
base flange portion to form a substantially T-shaped anchoring
portion for embodiment within a cast material forming said barrier
wall;
said head portion tapering sides being substantially symmetrical
about a plane passing through a longitudinal axis of the said
A-shaped portion;
a connecting web extending between said neck portion of said foot
portion and the wide end of said A-shaped head portion;
said A-shaped head portion having .[.a plurality of.]. recesses at
the wide end thereof .Iadd.and arranged .Iaddend.on opposite sides
of said connecting web and a pair of flanges, each extending
diagonally away from its associated recess at an angle
substantially equal to the angle formed by the tapering sides of
said A-shaped cross-section, said recesses forming self-energizing
water pockets to cause the flange of the associated water pocket
which may be filled with water to exert a greater compression force
against an engaging surface of a pipe inserted through said gasket
as a function of increasing water pressure applied upon said water
pocket; and
said annular member being formed from .Iadd.a linear extrusion,
.Iaddend.a length of said linear extrusion being curved and joined
at its ends to form said annular .[.ring.]. .Iadd.member.
.Iaddend.
5. The gasket of claim 4 wherein the thickness of said connecting
web is substantially less than the thickness of said neck portion
to enhance the bending flexibility of said gasket.
6. Th gasket of claim 4 wherein each of said recesses has a curved
concave surface portion to facilitate the intimate engagement of
its associated .[.flap.]. .Iadd.flange .Iaddend.with a pipe due to
increasing water pressure.
7. A bidirectional gasket for use in forming a fluid-tight seal
between a pipe and an opening in a barrier wall through which said
pipe passes, comprising:
an annular member of elastomeric material having a substantially
constant cross-section comprising a tubular head portion for
engaging a pipe and a foot portion comprising a base flange portion
and a neck portion of substantial thickness integrally joined to a
mid region of said base flange portion to form a substantially
T-shaped anchoring portion for embodiment within a case material
forming said barrier .[.walls.]. .Iadd.wall.Iaddend.;
said head portion having tapering sides which are substantially
symmetrical about a plane passing through a longitudinal axis of
said head portion;
a connecting web extending between said neck portion of said foot
portion and said head portion;
a pair of recesses provided in said head portion on opposite sides
of said connection web for forming water pockets;
said head portion having a pair of integral legs extending away
from said head portion in a generally radially outward direction,
each leg and connecting web defining sides of an associated recess;
and
said water pockets serving as water-tight enhancing means urging
the leg of the associated water pocket which may be filled with
water to exert a greater compressive force against an engaging
surface of a pipe inserted through said gasket as a function of
increasing water pressure.
8. The gasket of claim 7 wherein the thickness of said connecting
web is substantially less than the thickness of said neck portion
and said head portion to enhance the bending flexibility of said
gasket.
9. The gasket of claim 7 wherein the length of said legs is greater
than the length of said connecting web, said lengths being measured
generally along a line passing through the center of said
connecting web.
10. The gasket of claim 7 wherein .[.the.]. ends of said legs
engage the opening in said barrier wall, prior to insertion of a
pipe, and are adapted to selectively engage the pipe when the
gasket is deflected due to insertion of a pipe.
11. The gasket of claim 7 wherein .[.the.]. ends of said legs
extend a small predetermined distance into annular recesses
provided in the opening in said barrier wall and are adapted to
selectively snap out of said recesses when the gasket is deflected
due to insertion of a pipe.
12. The gasket of claim 7 wherein said legs substantially overlie
said connecting web.
13. The gasket of claim 7 wherein said connecting web has a
predetermined length, said recesses each having a depth
substantially equal to the length of said connecting web.
Description
FIELD OF THE INVENTION
The present invention relates to gaskets for providing a
water-tight seal between a manhole opening and a pipe extending
into said opening and more particularly to a novel bidirectional
gasket having self-energizing water pockets which enhance the
water-tight seal provided by the gasket whereby the sealing
pressure increases with increasing water pressure and wherein the
gasket design is capable of accepting pipe diameters over a wider
tolerance than conventional gaskets.
BACKGROUND OF THE INVENTION
Rubber connectors are typically utilized to provide a water-tight
seal between an opening in a manhole assembly and a pipe extending
into the opening. U.S. Pat. No. 4,159,829 assigned to the assignee
of the present invention discloses a conventional bidirectional
connector formed from an extrusion having a hollow, pear-shaped
head portion integrally joined to a T-shaped anchoring flange. The
extrusion is cut to length and curled to form a substantially right
cylinder configuration with the mating edges being joined. The
pear-shaped portion deflects from a radially inward orientation
upon insertion of a pipe. A single cavity extends through the head
portion to provide the head portion with added resiliency and
provides moderate sealing pressure. U.S. Pat. No. 4,508,355
assigned to the assignee of the present invention constitutes an
improvement over U.S. Pat. No. 4,159,829 by providing a gasket of
similar shape having a plurality of internal cavities extending
longitudinally through the head portion to provide the desired
resiliency while at the same time providing improved stability of
gasket configuration which yields a stronger and more uniform seal
around the exterior of the sewer pipe including portions of the
surface which may be significantly out-of-round.
The above designs nevertheless have the disadvantages of providing
a water-tight seal which weakens as the water pressure applied to
the gasket increases and which has very narrow tolerance limits
with regard to the range of pipe outer diameter which can be
accepted by a gasket thereby greatly increasing the number of
gaskets required to cover a large range of pipe outer diameters,
typically from 4" to 84".
BRIEF DESCRIPTION OF THE INVENTION
The present invention is characterized by comprising a
bidirectional gasket which retains all of the advantages of gaskets
of like design, as were described hereinabove, for example, and
which overcomes the above mentioned disadvantages as well as
provided other advantages not found in such conventional gaskets.
The gasket of the present invention is characterized by comprising
a T-shaped anchoring portion and a substantially A-shaped or
pear-shaped pipe engaging portion similar to those found in
conventional gaskets, as described hereinabove, for example. As a
departure from conventional design, the A-shaped portion is
provided with recess near its wide end which defines a pair of legs
the extend away from the head portion and act as water seal flaps.
The wide end of the A-shaped portion is joined to the anchoring
portion by an integral connecting web having a thickness which is
significantly reduced relative to the thickness of the adjacent
anchoring portion the connecting web greatly facilitating bending
of the connecting web and hence the gasket.
The connecting web cooperates with the legs and recess in the
A-shaped portion to form a pair of water pockets, one of which
becomes active dependent upon the direction in which the gasket is
deflected, to provide a water-tight seal which increases an
effectiveness with the increasing water pressure imposed upon the
gasket. The legs also provide significantly greater body contact
between the gasket and the pipe, further enhancing the water-tight
seal.
The flexibility and compressibility of the gasket are increased
through the use of voids in the head portion of the gasket. The
gasket material has a durometer comparable with conventional
gaskets of similar design, the durometer of the gasket also
contributing to the effectiveness of the "water pocket".
The bendability, flexibility and compressibility of the gasket, in
addition to providing a good water-tight seal, also permit the
gasket to accommodate a wider tolerance range of pipe
diameters.
The weight of the gasket is further reduced and the compressibility
is thus further enhanced by the continuous openings or voids
extending around the gasket and arranged within the A-shaped
portion of the gasket, which voids are capable of being filled with
a suitable liquid, in situations requiring reduced
compressibility.
The tip of apex of the A-shaped portion is provided with a
centering groove which serves to positively locate the internal
voids, thereby serving as the means for guiding insertion of a
hypodermic-type injection needle for penetration into the hollow
region and insertion of a suitable liquid for increasing gasket
volume and reducing compressibility.
A coupling web increases the gasket flexibility to such an extent
that the gasket, in addition to providing a wider tolerance range
for pipe diameter, provides an effective water-tight seal for pipes
whose longitudinal axes are offset from desired alignment by an
offset angle of as much as 15.degree. as compared with a maximum
offset angle of 10.degree. obtainable when employing conventional
gaskets of similar design.
In addition, integral tapered projections provided near the narrow
tip of the A-shaped portion serve as "wipers" which wipe lubricant
applied to the external periphery of the pipe to facilitate
coupling with the pipe, the wiping action further enhancing the
pipe/connector seal. The projection performing the wiping action is
ultimately compressed against the surface of the pipe.
OBJECTS OF THE INVENTION
It is therefore one object of the present invention to provide a
novel bidirectional gasket for providing water-tight gasket/pipe
seal which is superior to that of conventional gaskets of similar
design and which is accomplished in a gasket of reduced volume and
weight.
Another object of the present invention is to provide a novel
bidirectional gasket having water pockets designed to enhance the
effectiveness of the water-tight seal with increasing water
pressure imposed upon the gasket.
Another object of the present invention is to provide a novel
bidirectional gasket having increased flexibility as compared with
conventional gaskets of similar design through the employment of a
connecting web of significantly reduced thickness arranged between
and integrally joined with a T-shaped anchoring portion and an
A-shaped pipe engaging portion.
Still another object of the present invention is to provide a novel
bidirectional gasket for providing an enhanced gasket/pipe seal and
comprising a substantially A-shaped pipe engaging portion whose
narrow end is provided with integral wiping projections for wiping
lubricant from the pipe as it is inserted to further enhance the
water-tight seal provided by the gasket.
Yet another object of the present invention is to provide a gasket
providing a water-tight seal between a pipe and an opening in a
barrier wall, said gasket having a head portion engaging the pipe
and provided with extending legs which significantly increase the
contact area between the gasket and the pipe to further enhance the
water-tight seal.
BRIEF DESCRIPTION OF THE FIGURES
The above as well as other objects of the present invention will
become apparent from reading the accompanying description and
drawings in which:
FIG. 1 shows a sectional view of a gasket embodying the principles
of the present invention and in which a pipe has been inserted;
FIG. 2 shows a detailed sectional view of the gasket of FIG. 1 in
the position occupied by the gasket before insertion of a pipe;
FIG. 2a shows an enlarged sectional view of the water pockets
provided in the gasket as shown in FIG. 2;
FIG. 3 shows a sectional view of the gasket which is useful in
explaining the effectiveness of the pipe/gasket seal provided by
the water pocket; and
FIG. 4 shows a detailed view of the tip portion of the gasket.
DETAILED DESCRIPTION OF THE INVENTION
Making reference to FIGS. 1 and 2, the gasket 10 of the present
invention is preferably formed from a continuous extrusion of a
suitable synthetic elastomeric material.
The extrusion shown in cross-section, is comprised of an A-shaped
head portion provided with a recess R at the apex or tip of its
narrow end, as shown in FIG. 4. Tapered sides 12a and 12b terminate
in a pair of legs 12c and 12d at the wide end of the head portion
opposite recess R.
The pair of integral projections 12e and 12f arranged on opposite
sides of the recess R serve as wiping members for wiping lubricant
from an inserted pipe, as will be more fully described.
The gasket is formed of a suitable rubber or rubber-like material
selected to provide a gasket having a durometer of the order of
50-55 which is comparable to conventional gaskets, for example,
those gaskets of the type described in the aforementioned '355 and
'829 patents.
The volume, weight and compressibility of head portion 12 is
further reduced through the provision of cavities 12g and 12h which
are preferably symmetrically located with resepct to the aid of
symmetry S-S' of the cross-section of head portion 12, axis S-S'
extending perpendicular to the axis of cavities 12g and 12h and
extending through the mid-line of the anchoring portion and
connecting web as will be more fully described below. The cavities
12g and 12h are substantially continuous around the gasket.
Cavities 12g and 12h are preferably of different diameters, cavity
12h being larger than cavity 12g. The size and location of the
cavities, in addition to reducing the material present in the
gasket to provide the desired resilience, nevertheless provide
lateral stability to the structure which assures the maintenance of
configurational integrity, causing the desired function of the
gasket to be retained despite the large forces exerted upon the
gasket by the pipe inserted therethrough.
The gasket is further comprised of a T-shaped anchoring portion
which includes a neck portion 14 and an integral foot portion 16
which are adapted to be embedded into the cast material 22.
The A-shaped portion 12 is joined to neck portion 14 by an integral
connecting web 18 integrally joined to the wide end of head portion
12 and the end of neck portion 13 remote from foot portion 16. Web
18 has a thickness which is significantly reduced as compared with
the thickness of neck portion 14 to provide enhanced flexibility
and bendability of the gasket as will be more fully described.
The wide end of A-shaped portion 12 is provided with a pair of
curved recesses 12i, 12j shown in greater detail in FIG. 2a which,
together with connecting web 18 and legs 12c and 12d form a pair of
self-energizing water pockets P1, P2 which serve to increase the
effectiveness of the water-tight seal as the water pressure applied
to the gasket increases, as will be described more fully
hereinbelow.
In order to form a gasket of the desired size and diameter, the
extrusion is cut to a proper length and is formed into a circle
with the free ends of the gasket being bonded together to provide a
ring-like gasket. The joining and bonding techniques utilized for
forming the ring-like gasket are conventional and may incorporate
the techniques described in the aforementioned '355 and '829 whose
descriptions are incorporated herein by reference thereto.
Although the gasket of the present invention lends itself readily
to formation through the employment of an extrusion technique, it
is possible to mold the gasket, if desired.
The gasket is preferably embedded within a manhole assembly, for
example, by the use of conventional positioning rings, the
aforementioned method and apparatus being described in the
above-identified '829 patent with particular reference being made
to FIGS. 6 and 7 and the descriptive portions related thereto.
FIG. 1 shows the gasket 10 of the present invention installed in
opening 21 in sidewall 20 which may, for example, be the sidewall
of a manhole assembly and more particularly, a manhole base cast,
for example, from a suitable material such as concrete.
FIG. 2 shows a detailed sectional view of the gasket in cast
material 22 and in the undeflected position normally assumed prior
to insertion of a pipe.
FIG. 1 shows the manner in which pipe 24 is inserted within opening
21. Pipe 24 preferably, although not necessarily, is provided with
a tapered right-hand end 24a which facilitates insertion of the
pipe into the opening and the gasket. The outer periphery of pipe
24 is also preferably coated with a lubricant to further facilitate
entry of the pipe into the gasket.
FIG. 1 shows the pipe after insertion, the pipe originally being
moved from left to right, causing the gasket to undergo bending
from the undeflected position shown in FIG. 2 to the deflected
position shown in FIG. 1. The projection 12g permits easier
coupling by allowing the lubricant to remain in the immediate area
where the gasket and pipe surface meet. This ensures that the
proper amount of lubricant remains present to prevent tearing or
frictional wear of the gasket profile during coupling. When the
coupling action is completed, the lubricant typically used in
pipeline construction will actually create a frictional bond
between the gasket and pipe surface as the lubricant disperses. In
addition, the projection 12g is compressed between the main body
12a of the gasket and the pipe when the pipe is moved to its final
position.
The bending of the gasket serves to urge the legs 12c against pipe
24 to significantly increase the surface area contact between the
gasket and the pipe, especially when compared with the gaskets
disclosed in the '829 and '355 patents.
Self energized water pocket P1, in addition to blocking water from
passing from the external side of side-wall 20 between the gasket
and the pipe, further provides a self-energizing function wherein
the build-up of water pressure within pocket P1 applies an
increasing force upon head 12 and leg 12c, as shown in FIG. 3
causing the head 12 and especially leg 12c to apply increasing
pressure upon the surface of pipe 24, with the result that the
greater the water pressure, the better the seal between the gasket
10 and pipe 24. The increased surface contact between gasket and
pipe due principally to the legs 12c, 12d also contributes
significantly to the effectiveness of the water-tight seal. Also
the likelihood that an imperfection in the pipe surface will create
or cause a failure is greatly reduced.
Employing a gasket material having a durometer of the order of
50-55 increases the compressibility of the gasket, enabling the
gasket to deflect from the undeflected position to that of FIG. 2
to that shown in FIG. 1 and further enables the gasket flange 12c,
for example, to experience compression due to the build-up of water
pressure within the self-energizing pocket P1. The durometer of the
gasket, coupled with the voids 12g and 12h, enables the gasket to
accommodate a pipe diameter tolerance range which is significantly
greater than that of conventional gaskets of similar design due to
the reduction in physical volume and rubber durometer. In addition,
the gasket flexibility accommodates diameter deflection and/or
ovation in flexible pipe materials.
The profile of gasket 10 also accommodates greater angular
deflection and/or pipe misalignment as compared with conventional
gaskets. FIG. 1 shows the angle .alpha. of deflection which may be
as much as 15.degree. deviation from the desired longitudinal axis
while maintaining a good water-tight seal. This compares very
favorably with conventional gaskets of similar design which provide
a maximum deviation of 10.degree..
The legs 12c, 12d extend well beyond the head portion 12 and extend
to the opening 21 in wall 22 and preferably extend partially into
annular recesses in opening 21 as shown in FIG. 2. The leg 12c
snaps away from the position shown in FIG. 2 upon deflection of the
gasket. The penetration of the legs into opening 21 is chosen to
maximize the length of legs 12c, 12d while preventing the legs from
being locked in to the cast material and this prevented from
engaging pipe 24.
The coupling pressure of the gasket (in the absence of water
pressure in a water pocket) is comparable to conventional gaskets
of similar design due to the rubber durometer and overall volume
while at the same time providing a good water-tight seal which
increases in effectiveness due to the self-energizing water pocket
design described hereinabove.
The gasket of the present invention provides superior sealing
capabilities as compared with conventional gaskets of similar
design while being of reduced size and weight thus significantly
reducing the cost of materials and hence the cost of production.
The gasket design, size, volume and durometer further enable the
gasket to acclimate a wider tolerance of pipe diameter, enabling,
for example, gaskets of four cross-sectional sizes to cover a
complete range of pipe sizes from 4 inches to 84 inches diameter
pipe, as well as accommodating both rigid and flexible pipe.
A latitude of modification, change and substitution is intended in
the foregoing disclosure, and in some instances, some features of
the invention will be employed without a corresponding use of other
features. Accordingly, it is appropriate that the appended claims
be construed broadly and in a manner consistent with the spirit and
scope of the invention herein described.
* * * * *