Note: Descriptions are shown in the official language in which they were submitted.
The present invention relates gener~lly to the field
of plastic pipe fittings, and more particularly, is directed to
an improved pipe fitting construction system including integral
locking and sealing features.
In piping systems in general and plastic piping
systems in particular, it is the usual practice to provide
lengths of pipe in suitable increments, e. g., ten feet or
twenty feet, for use in constructing a pipe line of desired
size. Each pipe length is fabricated to the designed internal
diameter, usually by the exk~sion process, and then has its
ends worked as necessary to provide one bell or hub end and one
spigot end of predetermined interrelating design to allow
adjacent lengths of pipe to be joined in a secure and leak
proof manner.
~sual fittings, e. g., tees and wyes,are employed
where design criteria require, and such fittings form the
subject matter of the present invention. Fittings of smaller
sizes are generally molded or are otherwise formed for use with
pipe sections of equal diameter. In the case of larger
diameter work, the molding process cannot normally be
economically employed and accordingly it is common practice to
fabricate large diameter fittings of separate molded or
extruded plastic components and then to join the separate parts
together. For example when fabricating a wye fitting of twelve
inch diameter, the center part in the configuration of the wye
shape was first formed. Each of the three wye ends was then
equipped with a bell or hub of suitable configuration to
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7~ 76
receive and seal against the spigot end of an interconnecting length of
plastic pipe. In order to generate sufficient strength in each hub con-
nection and to assure a leak-proof fitting, a solvent weld or chemical
junction was first formed between a hub and one free end of the wye center
body. After all of the hubs were solvent welded in place, a second plastic
weld or peripheral heat junction was then applied at each connected hub.
These operations have proved to be time consuming, costly and subject to
frequent quality control rejections. The fitting construction of an aspect
of the present invention seeks to overcome all of the problems incident to
10 the present pipe fittingconstruction techniques.
It is therefore an object of one aspect of the present invention
to provide an improved pipe fitting construction of the type set forth.
It is an object of another aspect of the present invention to
provide a novel pipe fitting construction wherein the fitting center body
and end hubs are assembled without the need for solvent welding or chemical
sealing of the parts.
It is an object of another aspect of the present invention to
provide a novel pipe fitting construction wherein the fitting center body
and end hubs are assembled without the need for plastic welding or heat
20 sealing of the parts.
It is an object of yet another aspect of the present invention
to provide a novel pipe fitting construction w]lerein the fitting center
body and end hubs include self-sealing and self-locking cooperating con-
struction features.
It is an object of still another aspect of the present invcntion
to provide a novel pipe fitting construction including a center body having
a lock junction at each of its ends and hubs ~lich are connected to each
such end, each hub being provided with an inclined circular projection to
seat in and lock within one of the lock juncticns to affix the hub to the
~7~ ~ 76
fitting center body in a self-locking, leak-proof manner.
It is an object of y et another aspect of the present invention to
provide a novel pipe fitting construction wherein inlet and outlet ends of
the fitting center body are each formed with an exterior circular shoulder,
a circular lock and a circular gasket groove, a hub overfitting each such
end and being seated upon the shoulder, each hub being formed to include
an inclined inward projection to lock upon the circular lock and a gasket
positioned within the groove to seal the interconnection between a center
body end and its associated, locked hub.
It is an object of still another aspect of the present invention .
to provide a novel pipe fitting construction that is simple in design,
inexpensive in manufacture and trouble free when in use.
By one broad aspect of this invention, an improvement is provided
in a pipe fitting construction, the improvement residing in the combination
of: a central body of predetermined configuration and having at least one
end having an end terminus; a lock junction mean s formed in the end to
provide a self-locking interconnection; an end hub m~ans connectable to
the end at the self-locking interconnection to provide an enlarged connec-
tor for an adjacent length of pipe; and gasket means secured intermediate
the central body end and biasing against the end hub means to provide a
self-sealing interconnection.
By one variant thereof, the central body end terminates in an end
terminus and the lock junction means comprises a radially extending
shoulder which outwardly p~ojects from the outer central body periphery,
the shoulder being inwardly spaced fr~m the face.
By a variation thereof, the shoulder is contacted by a portion of
the end hub means.
By a further variation, the shoulder is contacted by the por~ion
in a circular arc.
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, 6
By yet another variation, the arc extends through three hundred
and sixty degrees.
By another variant, the lock j unction means comprises a radially
inclined lock and the end hub means comprises a radially inclined projec-
tion, the projection and the lock being of cooperating similar dimensions
wherein the projectionfits withinand issecured within the loc3c to
secure the end hub means to the central body.
By a variation thereof, the inclined lock extends circularly
about the central body end.
By a further variation, the inclined lock extends radially
inwardly from the o uter periphery of the end .
By yet another variation, the projection extends circularly about
the end hub means.
Byyet a further variation, the projection extends radially
in~rdly fromthe inner periphery of the end hub means.
By still another variant, the lock junction means canprises a
peripheral, radially outwardly extending shoulder spaced inwardly from the
end tenninus and an inwar~ly inclined lock positioned intermediate the
shoulder and the end terminus and a radially inwar~ly pr~jecting groove
20 intermediate the lock and the shoulder, the groove being adapted to receive
and secure the gasket means therein.
By a variation thereof, the shoulder extends circularly about
the outer periphery of the central body end.
By a further variation, the groove extends circularly about the
central body end.
By yet another variation, the lock comprises an inclined side
and a contiguous radi~lly aligned side.
By a further variation, the end hub means comprises an inwar~ly
inclined projection, the projection being definedby an inclined side and a
~ 7~ 76
continguous radially aligned side.
By a further variation, the end hub means comprises an inwardly
inclined projection, the projection being defined by an inclined side and
a contigucus radially aligned side.
By a further variation, the radially aligned side of the projec-
tion abuts the radially aligned side of the lock to prevent disassociation
of the end hub means from the central body end.
By yet a further variation, the inclination and length of the
projection inclined side is the same as the inclination and length of the
lock inclined side.
By a still further variation, the respective inclined sides and
radially aligned sides of the lock and the projection are in substantially
overall contact.
By yet another variant, the end hub means terminates inwardly in
an inward end and the lock junction means comprises a circular shoulder,
the inward end of the hub rneans contacting and seating against the circular
shoulder.
By a variation thereof, the lock junction means comprises a
circular, radially inwardly inclined lock and the end hub means comprises
a circular radially inwardly inclined projection, the projection being
aAapted to seat within and lock within the lock.
By a further variation, the lock and the projection are formed to
substantially the same cross-sectional configuration.
By another variation, the lock is spaced endwardly from the
shoulder.
By a still further varia~ion, the projection is spaced endwardly
from the hub means inward end.
By yet a further variationS the spacing of the lock from the
shoulder equals the spacing of the projection from the hub means in~ard ~nd.
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~ ~ 7~ 6
By another aspect of this invention, a method is provided for
fabricating a pipe fitting comprising a central body and an end hub com-
prising: formang in the outer periphery of the center body a radially
inwardly extending, circular lock near one end of the center body; forming
in the inner periphery of the end hub a radially inwardly projecting,
circular projection; forcing the end hub over the end of the center body
and seating the projection within the lock to provide a self-locking inter-
connection; and interposing a resilient gasket between the end of the
center body and the inner periphery of the end hub to provide a self-
sealing junction therebetween.
By a variant thereof, t he method includes the further steps offorming a circular recess in the outer periphery of the center body end
and seating a portion of the gasket within the recess.
By another variant, the method includes the further step of pro-
viding a shoulder projecting radially outwardly near the end of the center
body and contacting the shoulder with an end portion of the hub.
According to one embodiment of this invention, a fitting center
body member is formed in usual manner to the desired configuration, e.g.,
a wye or a tee having conventional predetermined inside diameter confornuu-g
to usual pipe sizes, for exa~ple, twelve inches, fourteen inches, and the
like. Fach end of the fitting center body is formed with a lock junction
means to receive and lock thereon a hub member in a leakproof relationshi~.
The hub m~mbers are preferably of usual hub design which may or may not
include a peripheral groove and gasket seated therein for joining the
spigot end of an adjacent length of pipe. F~ch hub member includes circular,
inwardly inclined projection means of suitable configuration to slide over
and lock upon the center bcdy lock junction means thereby to provide a self-
locking construction.
The lock junction means comprises generally a radially outwardly
7 ~
projecting shoulder which is spaced inwardly from each chambered end of
the fitting center body construction. An inwardly inclined, circular
lock is formed near the chambered end to receive and lock thereon
the cooperating circular, inwardly inclined projection means which
projects radially inwardly in the associated hub construction.
A circular, radially outwardly open groove is formed in each center
body end intermediate the outwardly projecting shoulder and the
inwardly inclined lock. In the preferred embodiment, the groove
is rectangular in cross-sectional configuration to receive and firmly
seat therein a resilient gasket for self-sealing arrangement between
the respective ends of the fitting center body and each respective
associated hub. Preferably, the gasket employed may be similar
to the gasket disclosed in a copending Canadian application entitled
"Pipe Bell and Gasket", which application was filed on June 23,
1981, Serial No. 380,388, and a divisional application therefrom,
Serial No. 429,988-4, filed August 6, 1983.
The lock junction means and the cooperating inwardly inclined
projection means provide a self-locking and self-sealing arrangement
between the fitting center body and the end hub and eliminates the
need for additional operations upon assembly of the parts such as
solvent sealing and heat welding.
In the accompanying drawings,
Figure 1 is a perspective view of the pipe fitting construction
of an aspect of the present invention;
Figure 2 is an enlarged, partial, cross-sectional view,
taken along line 2-2 on Figure 1, looking in the direction of the
arrows; and
Figure 3 is an enlarged, exploded, perspective view of
one locking junction and associated hub, partially broken away to
illustrate interior construction details.
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Referring now to the drawings, there is illustrated a
pipe fitting generally designated 10 of the type suitable for
usual plastic pipe use, for example, drain lines. In the
illustrative example, a fitting of twelve inch diameter will be
described. However, fittings of larger or smaller diameter can
be similarly constructed, and accordingly, all usual fitting
sizes are considered to fall within the aTr~it of
this invention.
The fitting 10 comprises a central body 12 of desired
configuration, e. g., the wye shape as illustrated. The
central body 12 is formed with the in line conduit 13 and the
branch conduit 14, which conduits include the fitting inlet
ends 16, 20 and fitting outlet end 18. Inlet hubs 22, 26
respectively overfit and join the central body 12 at the inlet
ends 16, 20. Similarly, an outlet hub 24 of the same
configuration overfits and joins the central bodY 12 at the
fitting outlet end 18. It is the essence of an aspect of this invention to
provide a self locking anu self sealing interconnection between
the respective central body ends and hubs 16, 22, 18, 24 and
20, 26. As above set forth, the respective hubs 22, 24, 26 can
be of any known configuration and design, either with or
without an internal groove for seating or sealing a gasket, as
may be desired to interconnect the fitting 10 with pipe lengths
(not shown) of a piping system.
Referring particularly to Figs. 2 and 3, it will be
seen that each end 16, lB, 20 of the central body 12 is molded
or otherwise formed to provide a circular, radially outwardly
extending shoulder 28. As best seen in Fig. 2, each hub 22,
24, 26 overfits its respective central body end 16, 18, 20 and
1 is pressed inwardly until its end 30 rests upon and abuts
against the shoulder 28. As illustrated, the shoulders 28 are
spaced inwardly from a respective end terminus 46 of the
central body 12 and thus serve to set and limit the distance
each end hub means 22, 24, 26 overfits its respective central
body end 16, 18, 20 as the fitting 10 is assembled. Each
shoulder 28 terminates in a plane that lies at right angles to
the axis of the central body main or branch conduit 13, 14.
Each central body end 16, 18, 20 is molded, machined
or otherwise treated, by using known plastic pipe forming
techniques, to provide a lock junction means 40 for
automatically and securely receiving and affixing a respective
hub 22, 24, 26. The lock junction 40 is inwardly spaced from
the central body end terminus 46 and is positioned intermediate
the end terminus 46 and the circular shoulder 28. The lock
junction 40 comprises a circular lock 42 which is defined by a
circular, inwardly inclined side 42 and an abutting, circular,
radially outwardly extending side 52. As best seen in Fig. 2,
each central body end 16, 13, 20 is additionally provided with
an outwardly open, circular groove or recess 32 which is
inwardly spaced from the inward terminus of the inclined side
50 of the lock 42. Preferably, as shown, the circular groove
32 is formed with parallel sides 54, 56 which extend at right
angles from the groove bottom 58, to receive and securely seat
the resilient gasket 34 therein. As above set forth, the
gasket means 34 is designed in accordance with the teachings of
the said copending application. The gasket preferably includes
a pair of inwardly spaced, integral, circular sealing rings 36,
38 which rings extend radially outwardly to bias and seal
7~
1 against a portion of the inner periphery 60 of a hub 22, 24,
26. Preferably, the gasket 34 is fromed to the same general
configuration as the circular recess 32 to firmly seat therein
to prevent displacement when the fitting is assembled.
Still referring to Figs. 2 and 3, each hub 22, 24, 26,
includes a hollow, cylindrically formed connecting end 62 of
size to tightly overfit the outer periphery of its associated
central body end 16, 18, 20. The connecting end terminates
inwardly at the hub end 30 and is provided with an inwardly
inclined inner projection 44 of circular, arrow-like
configuration to slip over the associated central body end 46
and to lock within the fitting central body lock 42. As
illustrated, the inwardly inclined projection 44 cooperates
with and locks inside of the central body lock 42 to prevent
disassocaiation of the hubs 22, 24, 26 from the central body 12
once the fitting 10 has been completely assembled. Each
inwardly inclined projection 44 includes an inclined side 64 of
dimensions, position and inclination which are substantially
identical tothe dimensions, position and inclination of the
corresponding inclined side 50 of the central body end lock
42. Similary, each inwardly inclined projection 44
additionally includes a radially inwardly extending side 66 of
dimensions and position which are substantially identical to
the dimensions and position of the corresponding radially
outwardly extending side 52 of the central body end lock 42.
The corresponding radially extending sides 52, 66 engage and
interlock, as best seen in Fig. 2, to prevent the hubs 22, 24
and 26 from being pulled or otherwise separated from the
fitting central body 12 once the fitting 10 has been
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~ 7~ 76
1 assembled. Each end 46 of the fitting central body 12 is
preferably angularly formed to provide least resistance to the
flow of liquids (not shown) as they enter the fitting 10 in the
direction indicated by the arrow 48.
In one configuration, the fitting center body 12 was
formed to a nominal 12 inch size having 12.5 inch outside
diameter and wall thickness of 0.39 inches. The circular
shoulders 28 were similarly dimensined to project outwardly
from the outer central body periphery a distance of 0.39
inches, thereby to engage and receive thereon the connecting
end 62 of a ~onventional hubs 22, 24, 26. In this
configuration, the hubs 22, 24, 26 were fabricated in usual
manner with inside diameter of 12.5 inches whereby the hub
could be applied over the central body end 16, 18, 20 in a
relatively tight engagement by applying axially directed forces
and acknowledging the natural resiliency of the plastic
material of the body and hubs. The inwardly inclined, circular
projection 44 of each hub was formed to project radially
inwardly from the hub interior periphery a maxium distance of
0.11 inches. Similarly, the circu~ar lock 42 of the lock
junction was formed to extend radially inwardly from the
central body outer periphery a maximum distance of 0.11 inches
and was formed to the same cross sectional configuration as the
circular hub projection 44. Accordingly, as each hub was
forced axially inwardly over its associated central body end,
the circular projections 44 were forced into association within
the respective locks 42. The plastic central body and hub
components deformed as necessary to make up the locked junction
between the parts and then naturally returned to substantially
7 ~
1 the unstressed dimensions and shape after the projection 44 was
fully seated within the associated lock 42.
In order to assemble the fitting 10 to provide a self
locking and self sealing construction, all of the ends 16, 18,
20 of the fitting central body are formed with the locking and
sealing construction as shown in Figs. 2 and 3. A circular,
resilient gasket is then seated within the central body end
circular groove 32 with the sealing rings 36, 38 projecting
peripherally beyond the outer periphery 68 of the central body
ends 16, 18, 20. Each hub connecting end is formed with a
inwardly inclined projection 44 for cooperation with the lock
42 provided in a central body end. The inner periphery 60 of
the hub connecting end 62 is maintained to substantially the
same diameter as the other periphery 68 of the center body end
16, 18, 20. After the parts 12, 22, 24, 26 have been formed as
illustred, each hub 22, 24, 26 is placed in axially aligned
juxtapostion to its associated central body end 16, 18, 20 and
then the hubs are urged inwardly over their respective
associated central body ends. The natural resilier.cy of the
plastic material comprising both the central body 12 and the
hubs 22, 24, 26 allows sufficient movement or give by either or
both flexing the central body ends 16, 18, 20 radially inwardly
and the hub connecting ends 62 radially outwardly to permit the
hub inward projection inclined side 64 to pass over the fitting
end 46 sufficiently until the hub projection engages and fully
seats within the central body end lock 42. In this position,
the hub end 30 contacts in overall circular engagement the stop
28. The natural memory of the plastic material forming the
central body 12 and the hubs 22, 24, 26 functions to naturally
76
and quickly return the parts to their designed configurations and dimen-
sions after the projection seats in the lock thereby to secure the parts
together.
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