Connector for tubular members

A connecting device for connecting together tubular members is comprised of a resilient sheet member in the form of a coil having at least partially overlapping surfaces. The inner diameter of the sheet member coil is less than the outer diameter of the members to be joined. A layer of heat sensitive adhesive bonding material is provided over the inner surface and subsequently after the formation of the connection on the outer surface of the sheet member coil. The sheet member coil is expanded to a larger diameter against the resiliently inwardly directed force of the sheet member and held in the expanded condition by heat sensitive adhesive bonding material. The expanded larger diameter is of a sufficient diameter to receive the ends of the members to be joined. Once the members to be joined are inserted into the coil, the sheet member coil may be heated whereby the heat sensitive adhesive bonding material melts allowing the sheet member to contract inwardly forming a tight bond between the inner surface of the sheet member and the members being joined. The connecting device may be utilized to connect a tubular member and an expandable tubular member. The connection formed by heating in such case results in the sheet member coil assuming a minimal degree of frustro-conical shape with a limited flow of the adhesive bonding material from the area over the expandable unit to the area over the tubular member. After application of the second layer of heat sensitive adhesive bonding material on the outer surface of the sheet member coil, the joined expandable unit to the tubular member is provided as an assembled unit ready for field application.

BACKGROUND OF THE INVENTION 
The present invention relates to improvements in devices to be used to 
connect together tubing and to connect tubing to expandable units. 
SUMMARY OF THE INVENTION 
The present invention enables the connecting together of tubular members 
and the connecting of a tubular member to an expandable tubular member. 
Furthermore, the present invention provides a means of securing tubing to 
the inner wall of a pipe in which the tubing may be mounted by means of 
the expandable unit. 
Briefly, in accordance with the present invention, a device is provided for 
connecting together tubular members. The device is comprised of a 
resilient sheet member in the form of a coil having at least partially 
overlapping surfaces. The inner diameter of the sheet member coil is less 
than the other diameter of the members to be joined. A first heat 
sensitive adhesive bonding material is applied to the inner surface of the 
sheet member coil. The sheet member coil is expanded to a larger diameter 
against the resiliently inwardly directed force of the sheet member and 
held in the expanded condition by at least one of the heat sensitive 
adhesive bonding materials. The expanded larger diameter is of a 
sufficient diameter to receive the ends of the members to be joined. Once 
the ends of the members to be joined are inserted into the coil sheet 
member, the coil sheet member may be heated whereby the heat sensitive 
adhesive bonding material holding the coil in the expanded condition melts 
allowing the sheet member to contract inwardly. Upon the cooling of the 
first heat sensitive bonding material, a tight and strong bond is formed 
between the inner surface of the sheet member and the joined tubular 
members. The cooled first heat sensitive bonding material forms a bond 
between the inner surface of the coil and the joined tubular members with 
the resilient sheet member coil providing support. After the first layer 
of heat sensitive bonding material cools, a second layer of heat sensitive 
bonding material is supplied to the outer surface of the sheet member 
coil. 
In another embodiment of the present invention, the device of the present 
invention is utilized for forming a connection between a tubular member 
and a tubular member adapted for expansion. The coiled resilient sheet 
member with the first heat sensitive adhesive bonding material applied to 
the inner surface is utilized to form a connection between a tubular 
member and a tubular member adapted for expansion. After forming the 
connection between the tubular member and the tubular member adapted for 
expansion, a second layer of heat sensitive bonding material is applied to 
the outer surface of the coiled sheet member. The expandable unit with the 
tubular member joined thereto may be placed within a pipe or the like 
whereupon subsequent heating of the expandable unit, the expandable unit 
expands causing the resilient sheet member to comply assuming a minimal 
degree of frustro-conical shape with a limited flow of the adhesive 
bonding material from the area over the expandable unit to the area over 
the tubular member. This subsequent heating causes bonding of the outer 
surface of the coiled sheet member to the inner surface of the pipe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings in detail, wherein like numerals indicate 
like elements, there is shown in FIGS. 1 and 2 a connecting device 110 in 
accordance with the present invention. Connecting device 110 is comprised 
of a resilient sheet member 112 in the form of a coil. Resilient sheet 
member 112 has overlapping surfaces at 114. In other words, the resilient 
sheet member 112 has at least partially overlapping surfaces which may 
form a bonding area between or around the two ends of the resilient sheet 
member. A first heat sensitive adhesive bonding material 116 is applied to 
the inner surface of sheet member coil 112. Various heat sensitive bonding 
materials may be used, including, but not limited to, various ethelyne 
vinyl acetate resins or a commercially available adhesive manufactured by 
the Bostik Company of Middleton, Mass. and sold under the name BOSTIK 
6323. Resilient sheet member 112 may be comprised of any suitable 
resilient metal material or synthetic plastic material. Suitable resilient 
sheet material may be stainless steel, brass, bronze, spring steel or 
other suitable resilient metalic material. Suitable resilient synthetic 
plastic materials may be polyethylene, polyolefin, vinyl or other suitable 
synthetic materials having the desired resiliency. 
Resilient sheet member coil 112 is formed or constructed to have an 
unstressed or resting diameter less than the tubing to be connected or 
joined. In other words, the initial free inner diameter of the connecting 
device 110 is less than the outer diameter of the tubing to be connected. 
In constructing the connecting device 110, resilient sheet member 112 is 
expanded to a larger inner diameter against the resiliently inwardly 
directed force of sheet member 112. Connecting device 110 is retained in 
the form of an expanded diameter by means of the first inner heat 
sensitive adhesive bonding material 116. The heat sensitive adhesive 
bonding material may perform this function by preventing movement of at 
least one of the ends of the overlapping coil as shown in FIG. 3 at 121 
without any adhesive appearing between the overlapping surfaces of the 
coil sheet member 112. Alternatively, as shown in FIG. 4, the first layer 
of heat sensitive adhesive bonding material l16 may appear partially 
between the overlapping surfaces as shown at 125. Alternatively, as shown 
in FIG. 5, the first layer or inner layer of heat sensitive adhesive 
bonding material 116 may entirely fill the area between the overlapping 
surfaces of coil sheet member 112 as shown at 127. Therefore, the 
resilient sheet member 112 is held in the expanded condition by the heat 
sensitive adhesive bonding material 116. The coiled sheet member is 
released and allowed to contract when the heat sensitive adhesive bonding 
material is raised to its melting point temperature. 
In many applications, it may be desirable or necessary to prevent the flow 
of adhesive into the internal space of the tubular members being joined. 
Preventing this flow, prevents any obstruction within the tubular members. 
This may be accomplished as shown in FIG. 6 wherein the tubular members 
118 and 120 to be joined are provided with mating ends 130 and 132 in the 
form of a chamfer. However, it is understood that other mating end forms 
may be provided on the ends of tubing 118 and 120, although chamfering as 
shown is presently preferred as it provides the additional advantage of an 
automatic centering function between the tubing to be joined. 
Alternatively, a narrow thin ring sheet closure or tape, such as polyester 
tape may be utilized to wrap the junction of tubing to be joined to 
prevent the flow of adhesive into the tubing. One such suitable polyester 
tape is commercially available under the name "MYLAR" from the E. I. du 
Pont de Nemours & Co. 
After the formation of a connection between tubular members, as shown in 
FIG. 6, a second layer of heat sensitive adhesive bonding material 117 may 
be applied to the outer surface of the sheet member coil 112 as shown in 
FIG. 6. This is a preferred embodiment where it may be desirable or 
necessary to anchor tubing to the internal surface of another conduit, 
such as the pipe. In this manner, the outer surface of the connector may 
be bonded to the internal surface of the pipe. It is intended that the 
second layer of adhesive 117 may be applied to all of the embodiments 
shown in FIGS. 1 through 5 after the formation of a connection. The second 
layer of heat sensitive adhesive bonding material may be comprised of the 
same type of material as discussed above with respect to the first heat 
sensitive adhesive bonding material 116. 
Referring now to FIG. 7, there is shown another embodiment of the present 
invention wherein a connecting device 140 in accordance wth the present 
invention is utilized to join together a tubular member 142 and an 
expandable tubular member 144. Expandable tubular member 144 may be of a 
construction similar to that described in U.S. Pat. Nos. 4,394,202 and 
4,410,391, which are assigned to the assignees herein. Expandable tubular 
member 144 may be comprised of a cross-linked tubular member which is 
preshrunk and which expands to its normal condition upon heating. The 
subject matter of the two aforesaid patents is incorporated herein by 
reference the same as if set forth at length. The expandable tubular 
member 144 may be provided with its own outer adhesive layer 146 and with 
an internal coil spring element 148 to provide added direction and force 
control in its expansion process and in maintaining the expanded unit in 
its expanded condition for extended periods of time, as it is intended to 
be expanded within a pipe. 
Referring jointly to FIGS. 7 and 8, connector device 140 is comprised of a 
coiled sheet member 152 with a first inner heat sensitive adhesive layer 
156 and a second outer heat sensitive layer 157 which was applied 
subsequent to the formation of the connection. The combination of adhesive 
layers 156 and 157 may form a chamfered edge as shown at 159. Tape 160, 
such as Mylar tape or other suitable polyester tape, may be applied at the 
junction of tubular member 142 and expandable tubular member 144 prior to 
the application of connecting device 140 to prevent the flow of any 
adhesive 156 into the joint. Connecting device 140 is then heated to form 
a connection between tubular member 142 and expandable tubular member 144. 
Upon melting of the heat sensitive adhesive and contraction of the coiled 
sheet member 152, and upon subsequent cooling of heat sensitive adhesive 
layer 156, a strong connection is formed between tubular member 142 and 
expandable tubular member 144. 
Upon formation of the connection between tubular member 142 and expandable 
tubular member 144, and after cooling of the first layer of heat sensitive 
adhesive material 156, a second layer of heat sensitive adhesive material 
157 is applied to the outer surface. This second layer of heat sensitive 
adhesive material is intended to provide a bond between the connecting 
device and the internal surface of a pipe into which the expandable unit 
and the connecting device are to be inserted, with it being intended that 
the expandable tubular member 144 is then expanded within the pipe and the 
second layer of adhesive 157 along with adhesive layer 146 forms a bond to 
the pipe. 
It is intended that the expandable unit or expandable tubular member 144 is 
to be expanded by heating to engage the containing pipe. In this process, 
a bulb will form at the end to engage that pipe fitting in which it is 
placed. This will provide a pressure seal and structural bond under a 
degree of geometric control exerted by the resilient sheet member. 
As described in the aforesaid reference patents, expandable tubular member 
144 with tubular member 142 is intended to be mounted within a pipe 162 or 
the like. Pipe 162 may be a pipe for supplying natural gas which is 
connected to a gas main, not shown, by means of a "T" connector 164. It is 
understood that the bulb end of expandable unit 144 may be expanded in any 
suitable connection or union in the pipe, including elbows, unions or the 
like in addition to "T" connectors. Tubular member 144 in its unexpanded 
state, with tubular member or tubing 142 connected thereto, is inserted 
into the pipeline 162 in the direction of arrow 166 from an access point, 
such as within the basement of a building, until the unexpanded tubular 
member 144 is within "T" connector 164. A heating device placed within 
tubular member 144 is then activated causing expandable tubular member 144 
to expand as shown in FIG. 9. For clarity in description, the expanded 
tubular member in FIG. 9 will be given the numeral 174 with the expanded 
spring being number 168. FIG. 9, in solid lines, illustrates the end 
result after tubular member 144 has been expanded and bonded in the 
pipeline and after a boring device has been subsequently utilized to make 
an opening 170 in the end of the expanded unit 174 for gas or other fluid 
flow after pressure testing of the new elements in place, as inserted and 
bonded to the existing containing pipe and end fitting. 
Reference should now be had jointly to FIGS. 9 and 10. As shown therein, 
upon the expansion of expandable tubular member or unit 144 to its 
expanded state, referred to as 174, by the heating of expandable unit 144, 
coiled sheet member 152 is caused to assume a conforming limited degree of 
frustroconical transition shape with the larger diameter being over the 
expanded unit 174 and the smaller diameter being over tubing 142. The 
heating and expansion of unit 174 also causes a limited amount of flow of 
the inner layer of adhesive 156 from area 178 over expandable unit 174 to 
area 180 over tubular member or tubing 142. The heating also causes a 
bonding of the outer layer of adhesive 157 at 182 to the inner surface of 
pipe 162. In this manner, not only does the conecting device 140 enable 
the connection together of two tubular members and accomodates their 
diameter transition after the formation of the connection, but it also 
enables the bonding of tubing 142 to the inner surface of a pipe in which 
the assembly is mounted as may be required by certain regulations in the 
gas distribution industry or other regulations, to provide restraint and 
structured anchorage of axial forces which may appear on the inserted 
tubing and prevent their appearance in the fabric of the expanding member. 
In a preferred embodiment, tubular member 142 may be comprised of a 
straight section of a relatively short length. For example, preferably, 
tubular member 142 may be comprised of a length of two to three feet or 
other suitable length selected in the range of one to four feet. The free 
end, or the end opposite to connecting device 140, not shown in the 
drawings, would be connected by a similar connecting device to a coil of 
flexible tubing prior to being inserted into the line. The providing of a 
selected length of straight tubing enhances the ability to feed the 
completed assembly of the expandable unit or expandable tubular member 144 
into the line. This provides a significant advantage in being able to feed 
an assembled unit through a section of line which not infrequently extends 
for distances of up to 100 feet or more. 
The present invention may be embodied in other specific forms without 
departing from the spirit or essential attributes thereof and, 
accordingly, reference should be made to the appended claims, rather than 
to the foregoing specification as indicating the scope of the invention.