U.S. patent number 3,574,313 [Application Number 04/771,818] was granted by the patent office on 1971-04-13 for wraparound closure sleeve.
This patent grant is currently assigned to Raychem Corporation. Invention is credited to Ken Tanaka.
United States Patent |
3,574,313 |
Tanaka |
April 13, 1971 |
WRAPAROUND CLOSURE SLEEVE
Abstract
A closure sleeve for pipes or the like constructed from a piece
of independently dimensionally heat unstable material, that is,
material which will return to its original shape and dimensions
upon application of heat alone. The sleeve is split and provided
along one edge with a plurality of preshrunk tabs which are folded
back over the sleeve. A plurality of corresponding slots are formed
adjacent the other edge of the sleeve and the material of the other
edge folded back over the slots. To install the closure member, the
piece of material is roller into tubular form and the tabs inserted
into the slots and the part then heat recovered.
Inventors: |
Tanaka; Ken (San Jose, CA) |
Assignee: |
Raychem Corporation (Menlo
Park, CA)
|
Family
ID: |
25093049 |
Appl.
No.: |
04/771,818 |
Filed: |
October 30, 1968 |
Current U.S.
Class: |
138/99; 138/168;
285/381.4; 174/DIG.8 |
Current CPC
Class: |
F16L
47/22 (20130101); B29C 61/10 (20130101); Y10S
174/08 (20130101) |
Current International
Class: |
B29C
61/10 (20060101); B29C 61/06 (20060101); F16L
47/00 (20060101); F16L 47/22 (20060101); F16l
025/00 () |
Field of
Search: |
;138/96--99,168,178,110,147--149 ;156/162 ;52/108 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jaudon; Henry S.
Claims
I claim:
1. A heat recoverable closure member comprising an elongated
independently dimensionally heat unstable member having a pair of
edge portions which can be brought into adjacency to form a tubular
member, a first of said edges having a plurality of tab means
formed thereon, said tab means being folded back over said member,
said member having a plurality of slots formed adjacent the other
edge portion thereof for receiving said tab means and retaining
said member in tubular shape, in closure operation the free end
portions of said tab means abutting the interior surface of said
other edge portion.
2. The member of claim 1 wherein said member is provided with a
flap adjacent said other edge portion and covering said slots.
3. The member of claim 1 wherein said tab means are
prerecovered.
4. A heat recoverable closure comprising a piece of independently
dimensionally heat unstable material having a pair of edge
portions, a plurality of tabs being formed along one of said edge
portions, said tabs being folded back over said piece of material,
the other edge portion of said piece of material being folded back
to form a flap, said piece of material having a series of slots
formed therein adjacent said flap, said tab means being inserted
into corresponding slots to form said piece of material in tubular
shape, said flap serving to maintain said tab means in said slots
during heat recovery of said member, the free end portions of said
tab means abutting the interior surface of said other edge
portion.
5. The member of claim 4 wherein said tab means are heat recovered
prior to being inserted in said slots.
6. The member of claim 4 wherein the inner surface of said piece of
material is covered with sealing material.
7. A heat recoverable closure member comprising an elongated
independently dimensionally heat unstable member having a pair of
edges which can be brought into adjacency to form a tubular member,
a first of said edges having a plurality of tab means formed
thereon, said tab means being folded back over said member, said
member having a plurality of slots formed adjacent the other edge
thereof for receiving said tab means and retaining said member in
tubular shape, said member being provided with a flap adjacent said
other edge and covering said slots, that surface of said member
which in closure operation is the inner surface being coated with
sealing material.
Description
BACKGROUND OF THE INVENTION
There are many instances where it is desirable to provide a
sealing, insulating or protective closure member for elongated
objects such as cables, pipes or the like where the ends of the
elongated objects are not accessible, or, if accessible, where it
is undesirable to disconnect or otherwise displace them from their
original position. One such closure member is disclosed in U.S.
Pat. No. 3,379,218 which is assigned to the assignee of the present
application. Another such disclosure member is disclosed in U.S.
Pat. application Ser. No. 506,161, filed on Nov. 3, 1965 now U.S.
Pat. No. 3,355,906 by Roger H. Ellis and assigned to the assignee
of the present invention. Still another such closure member is
disclosed in U.S. Pat. application Ser. No. 731,200 filed May 22,
1968 by Richard W. Muchmore and also assigned to the assignee of
the present application. The disclosures of this patent and these
applications are incorporated herein by reference. While each of
the closure members disclosed in the aforementioned patent and
applications are satisfactory in use, they each present some
fabrication requirements that, for economic reasons, are not
desirable in all situations.
SUMMARY OF THE INVENTION
According to the present invention a heat recoverable closure
member is provided which can be simply and easily fabricated from
extruded material, either in sheet form or in tubular form. The
extrusion in tubular form is particularly desirable because of the
ease in then imparting the material with the property of elastic
memory. After the tubular material is expanded, it is
longitudinally split to form a more or less flat sheet. One edge of
the sheet is then cut to form a plurality of tabs which are folded
back over the sheet. A row of slots is made adjacent the other edge
of the sheet and the material of that edge folded back over the
slots. When the closure is to be installed, it is wrapped around
the pipe or the like to be protected and the tabs inserted in the
slots so that a tubular member is formed. The sleeve can now be
heat recovered around the object, the fold of material beneath the
slots preventing the tabs from being pulled out of the slots. The
closure member of the present invention does not require an
external and separate closure device to hold the two edges of the
sheets together and it provides a very low profile and readily
follows irregular contours in the object to be covered. The closure
sleeve of the present invention is particularly useful where it is
desired to protect the joint or junction where two pipes meet,
particularly where the pipes are of large diameters such as water
supply pipes.
It is therefore an object of the present invention to provide a
heat recoverable closure member.
It is another object of the present invention to provide such a
member which is relatively inexpensive to fabricate and easy to
install.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the closure member of the present
invention after its initial fabrication;
FIG. 2 is a perspective view of the closure member of the present
invention after the tabs and sealing flap have been folded;
FIG. 3 is a cross-sectional view taken along lines 3-3 of FIG. 2
after folding has been completed; and
FIG. 4 is an enlarged sectional view showing the closure member of
the present invention after it has been secured in tubular
form.
DESCRIPTION OF THE INVENTION
As mentioned above, the closure member of the present invention
utilizes an independently dimensionally heat unstable member. In
general, such a member is made of a material capable of having the
property of elastic or plastic memory imparted thereto which is
heated to above its recovery temperature and expanded under
pressure to a configuration greater than its normal configuration
and then cooled while kept under pressure. A part treated in this
manner will retain its expanded position until it is again heated
to its heat recovery temperature at which time it will recover to
its original shape. Examples of such heat recoverable material is
found in Currie U.S. Pat. No. 2,027,962 and Cook et al. U.S. Pat.
No. 3,086,242, the disclosures of which are incorporated herein by
reference. Polymeric materials which have been cross linked by
chemical means or by irradiation, for example, with high energy
electrons or nuclear radiation, are preferred for use in the
present invention. Noncrystalline polymeric materials exhibiting
the property of plastic or elastic memory, such as polyurethane,
ionomers, etc., could also be used in practicing the present
invention. Since the closure members of the present invention can
be made from material having either plastic or elastic memory, the
terms "elastic memory" and "plastic memory" are used
interchangeably and are intended to be mutually inclusive.
According to the present invention, a flattened sheet of material
having the property of elastic memory, that is, of being heat
recovered, is used, the piece of material either being extruded or
molded in the flattened form, or, preferably, being extruded in
tubular form and then expanded, for example, in the manner taught
in the aforementioned Cook et al. patent and then slit
longitudinally. Such a flattened piece of material is shown at 10
in the drawing. The piece of material 10 is provided with a series
of tabs or fingers 11 along one edge. These tabs 11 can be cut,
stamped, or formed in any other suitable manner. The piece of
material 10 is also provided with a series of slots 12 which
preferably correspond, in number and spacing to the tabs 11. The
slots 12 are formed more or less adjacent the end of the piece of
material 10 remote from the end on which the tabs 11 are formed but
are spaced inward of the edge so that enough material is left to
form a flap that can be folded back over the slots along a line
13.
FIG. 2 shows the member after the flap 14 has been formed by
folding the piece of material 10 along the line 13. FIG. 2 also
shows the tabs 11 folded back. The folds are made by hot-folding
the material at a temperature just below its recovery temperature.
The tabs or fingers 11 are then prerecovered so that their
longitudinal recovery is released. This selective shrinking of the
tabs is preferably done by placing a large block of copper or other
highly heat conductive material on the remainder of the material 10
and exposing the fingers to a hot air blast or the like. The copper
block serves as a heat sink which prevents the remainder of the
material from being heated to its recovery temperature. The
recovery of the fingers results in their being thicker and stronger
than the rest of the material. If desired, the fingers may be
folded along a line slightly displaced from where they meet the
remainder of the material so that their alignment will be more
certain. If this is done, the portion of the material which is
folded back with the fingers is also heat recovered. It has been
found that the proper length of the fingers is a balance between
the desirability of having them short so that they are easier to
make and install, and the necessity to have them of sufficient
length that they will not pull out of the slots 12 once they have
been installed therein. FIG. 3 shows the closure member after the
folds have been completed.
FIG. 4 shows the manner in which the closure member is installed.
As can be seen, the piece of material 10 is rolled into tubular
form and the tabs 11 are passed through respective slots 12. The
closure member can then be heat recovered around the object it is
to protect. The flap 14 serves a dual purpose. First, it covers the
slots 12 so that a complete seal is formed. Second, it serves to
hold the tabs 11 in place during recovery so that they cannot pull
out of the slots 12. Preferably, the entire inner surface of the
material 10 and the flap 14 are covered with a suitable mastic or
hot-melt adhesive so that a bond is formed between the closure
member and the object on which it is recovered.
The closure member of the present invention is particularly useful
in protecting joints or junctions of large diameter pipes such as
water supply pipes. These pipes may have diameters as large as 6
feet or more which requires that the length of the piece of
material 10 be on the order of 20 feet. To form such a closure
member, it has been found desirable to expand a piece of tubing of
suitable length longitudinally rather than diametrically and then
slit it along its length. The tabs 11 are then formed on one end of
the expanded tubing while the slots 12 and the flap 14 are made at
the other end.
Because of the length of such a closure member, the more
conventional methods of heat recovering it are not always wholly
satisfactory. In place of such conventional methods as hot air
blowers or a torch, the closure member may be recovered by
combining it with pyrotechnic materials in the manner taught by
Wetmore application, Ser. No. 586,954 filed Oct. 17, 1966, and
assigned to the assignee of the present application and Deal et al.
application Ser. No. 727,074, filed May 6, 1968, and also assigned
to the assignee of the present application. The disclosures of both
of these applications are incorporated by reference herein. As
disclosed in these applications, suitable pyrotechnic material for
use in combination with the closure sleeve of the present invention
are aluminum trichloride and water or a fabric impregnated with
potassium nitrate. As disclosed in the aforementioned applications,
these pyrotechnic materials may be combined with other material
such as greases or may be structurally combined with heat shields
or the like.
The invention may be embodied in other specific forms not departing
from the spirit or central characteristics thereof. The present
embodiment is therefore to be considered in all respects as
illustrative and not restrictive, the scope of the invention being
indicated by the appended claims rather than by the foregoing
description, and all changes which come within the meaning and
range of equivalency of the claims are therefore intended to be
embraced therein.
* * * * *