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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates to a new and improved chemically-dilated,
elastomeric sleeve, and more particularly to an improved apparatus for
connecting the opposite edges of such a sleeve when it is wrapped around
an elongated pipe, cable, conduit, or similar member.
It has been known heretofore that certain types of shrinkable protective
tubing may be used for protecting joints, fittings and welds by which
pipes, cables, conduits, and other elongated members are joined, one to
the other, in an elongated string. One well-known type of material for
forming such protective sleeves is a heat shrinkable type, which, when
applied over a joint and subjected to heat, shrinks tightly into contact
with the members forming the joint.
These types of sleeves and means for connecting them about a pipe, cable or
the like are disclosed in the following U.S. Pat. Nos.: 3,379,218;
3,530,898; 4,218,814; 4,241,119; 4,371,578; 4,442,154; 4,532,168; and
4,541,145.
Another type of shrinkable tubing material, and that to which the present
invention is particularly addressed, is a shrinkable protective tubing
which has been dilated with chemicals to bring the same to a dilated or
enlarged state. This type of tubing remains dilated or enlarged so long as
it is kept out of contact with the air. However, once the tubing contacts
ambient air, it shrinks back to its initial size without any application
of heat.
A device for joining the opposite sides of such a sleeve is disclosed in
U.S. Pat. No. 4,607,866, also issued to the inventor of the present
application. The prior disclosure of this patent is hereby incorporated by
reference.
The device disclosed in U.S. Pat. No. 4,607,866 comprises rods that extend
through passageways extending along the opposed edges of the sleeve.
Alternating and opposing male and female members project from the rods
through apertures in the sleeve edges to interlock the rods together, to
thus retain the sleeve edges in a juxtaposed position.
These rods, however, are not directly attached to the sleeve, and as such
the lock is not as positive as it could be. Additionally, since the
sleeves are dilated both longitudinally and laterally, a longer rod is
required to accommodate the lateral dilation or expansion of the sleeve.
Thus, when the sleeve shrinks, the lock is relatively loose because of use
of the longer rod.
Further, the shrinkable protective tubing utilized heretofore has required
the use of a "flap". The function of the flap is to prevent any moisture
or water from seeping underneath the sleeve through apertures created by
the various locking devices. The flap extends below these apertures,
protecting the underlying pipe or member from moisture. The inclusion of a
flap on the protective tubing not only complicates manufacture but also
creates difficulty in the proper placement of the protective tubing or
sleeve on a pipe or other member.
The present invention contemplates an improved locking apparatus formed as
an extension and integral part of the opposed edges of a
chemically-dilated, elastomeric sleeve that shrinks upon exposure to
ambient air. The apparatus provides a positive lock that more securely
joins the opposed edges of the sleeve. The locking apparatus of the
present invention also facilitates installation of the sleeve about in
situ piping.
Additionally, the present invention does not require the use of a flap,
since no aperture is created by the locking device of the present
invention.
SUMMARY OF THE INVENTION
The present invention is directed to a protective sleeve that includes a
sheet of sleeve-forming, chemically-dilated, elastomeric material which
shrinks upon exposure to ambient air. The sheet has first and second
opposed edges that can be brought into adjacency when the sleeve is placed
in position about a pipe, cable, conduit or similar member. The sleeve
further includes first and second locking members extending from
respective ones of the first and second opposed edges along the lengths
thereof as an integral part of the sleeve. The locking members are formed
of a material that is dimensionally stable upon exposure to air and that
is substantially more rigid than the elastomeric material from which the
sleeve is formed. The locking members are adapted to engage one another to
retain the first and second opposed edges of the sleeve in adjacency.
The locking members may further include flange portions or members by which
the locking members are adjoined to the edges of the sleeve. The flange
portions may be formed of the elastomeric material. Alternatively, the
flange members may be formed of the same material from which the locking
members are formed. The flange members may be high-frequency welded to the
opposed edges of the sleeve.
The first locking member may comprise a male connector member extending
along the length of the first sleeve edge, and the second locking member
may comprise a female connector member extending along the length of the
second sleeve edge. The male and female connector members are adapted to
matingly engage to retain the opposed edges of the sleeve in adjacency.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the protective sleeve of the present
invention; and
FIG. 2 is a fragmentary side view of the sleeve of the present invention
wherein the opposite edges of the sleeve have been brought into an
interlocking relationship.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings in further detail, there is shown in FIG. 1 a
sheet of sleeve-forming material converted into a tubular configuration or
sleeve generally designated 5. The sleeve is formed of an elastomeric
material of any suitable and stretchable material such as rubber or
plastic. One advantageous material for the sheet 6 which forms the sleeve
is ethylene propylene diene monomer (EPDM) and another is
polyvinylchloride (PVC).
The material forming sheet 6 is preferably chemically-dilated, as, for
example, by application of a solvent to the material of the sleeve. This
causes the sleeve to become enlarged or dilated in size. At this stage the
sleeve-forming material may be inserted in a laminated, sealed pouch for
shipment and storage until it is ready for use. Thereafter, it may be
removed from the pouch for installation. When the solvent evaporates or
volatizes by exposure to ambient air, the sleeve simply shrinks back from
its dilated or enlarged size to its original size.
Sleeve 5 has opposed first and second side marginal edges or areas 20 and
22 which are brought into adjacency with respect to each other when the
sleeve is formed into a cylindrical configuration, as illustrated in FIG.
1. This is the configuration in which the sleeve is normally used when it
is placed about a pipe, cable, conduit or similar member.
As shown in FIGS. and 2, protective sleeve 5 further includes a lock or
engagement apparatus 10 for adjoining the opposed edges 20, 22 of the
sleeve when it is placed about a pipe or the like. The lock includes a
male member 12 and a female member 14 located at the opposed sides 20 and
22, respectively, of sleeve 5. Male member 12 further includes a flange
portion 12a and female member 14 includes a flange portion 14a.
In one embodiment, flange portions 12a and 14a are formed of the same
material as sleeve 5, i.e. a chemically-dilated, elastomeric material
which shrinks upon exposure to ambient air, e.g. PVC. Locking members 12
and 14, however, are formed of a material that is substantially more rigid
then the elastomeric material so as to provide a rigid lock that securely
joins the opposed edges of the sleeve. Preferably, locking members 12 and
14 are formed of such materials as polypropylene or polyethylene.
The flange portions 12a,14a and member 12,14 may be co-extruded, and the
flanges secured to the respective edges of the sleeve by, for example,
high frequency welding. The thickness of the flanges would be
approximately the same as that as the sleeve, i.e. about 0.0042 of an
inch.
In another embodiment, the flanges would be formed of a rigid material that
does not dilate when exposed to chemicals utilized to treat the sleeve
material. The flanges may be formed of the same material from which
members 12,14 are made, and they would be thinner than the sleeve, i.e. on
the order of about 0.0021 of an inch. The flanges may again be welded to
the edges of the sleeve.
As can be seen in FIG. 1, the male locking member 12 extends along the
entire length of edge 20 of sleeve 5, and the female locking member 14
similarly extends along the entire length of edge 22. This feature
advantageously provides an interlocking action along the entire length of
the respective opposed edges 20,22 when they are brought in adjacency
relative to each other.
As illustrated, locking member 12 may include a ridge or a longitudinally
extending projection 12b that extends from body 12c of locking member 12.
Female locking member 14 includes a groove or recess 14b in its body 14c
that is sized and shaped to matingly receive ridge or projection 12b.
As noted above, the present invention does not require the use of a flap to
prevent water or moisture from seeping underneath the sleeve and into
contact with the pipe or other member about which the sleeve is secured.
The device of the present invention, however, may further include a small
bead 16, for example one made of butyl rubber mastic applied along the
length of the female groove 14b. The use of bead 16 provides a seal
through which moisture or water will not penetrate. This bead forming the
waterproof seal may be approximately 0.040 inches in diameter. After
mating, the bead spreads out to form a substantially waterproof seal. It
should be understood that in the context of the present invention locking
members 12 and 14 may take some other form, configuration or shape which
provides the interlocking action sought by the present invention.
In use, sleeve 5 may be pre-molded to the approximate configuration of a
pipe, cable, conduit or similar member to which it is to be secured,
although it will be somewhat larger in size to permit it to be slipped
over the juncture of two such members, for example. The male and female
members 12 and 14 will be interconnected with one another and sleeve 5
will thus be loosely retained in position surrounding and protecting the
area to which it is to be joined. As the material 6 of sleeve 5 is exposed
to the ambient air, it begins to shrink. The locking members 12,14,
however, are dimensionally stable when exposed to the ambient air. Thus,
they do not shrink. Once the sleeve has shrunken sufficiently to engage
the pipe, further shrinkage will be precluded. At this point, the entire
sleeve will be tightly engaged throughout its full length with the cable,
pipe, conduit, or like member.
As the sleeve material 6 shrinks to the diameter of the member on which it
is used, the locking action provided by the locking apparatus 10, i.e.
members 12,14, increases. That is to say, ridge or projection 12b of
locking member 12 is more securely engaged within recess or groove 14b of
locking member 14.
The protective sleeve of the present invention may be configured in various
dimensions. For instance, it may have a width of 12 or 16 inches. If the
sleeve is 12 inches wide, then locking members 12,14 will be approximately
12 inches long. The sleeve of the present invention may be used on smaller
pipes or larger pipes, for example, pipes 54 inches in diameter.
As it is known in this art, the material 6 from which sleeve 5 is formed is
extremely pliable. In the dilated state, it loses approximately 50 percent
of its tensile strength but regains that strength upon exposure to ambient
air. The locking apparatus of the sleeve of the present invention provides
a hard locking face and thus a secure lock as the sleeve shrinks and
conforms to the configuration of the pipe, for example, on which it may be
used.
After reading the foregoing detailed description, it will be apparent to
those skilled in the art that various changes may be made in the
non-essential features of the present invention, without departing from
the spirit and scope of the invention as defined in the accompanying
claims.
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