Disengagement tool for use with a pipe joint assembly

A disengagement tool for a coupling assembly including a receiving tubular member for receiving a first tubular member, the receiving tubular member having an inner portion defining an inner bore dimensioned to receive one end of the first member and an outer portion defining an internal annular cavity intersecting the inner bore and projecting radially therefrom and a split lock ring disposed in the annular cavity and adapted to expand circumferentially therein during insertion of the first tubular member into the receiving tubular member. Forming the tool are parts with actuator end portions for engaging circumferential edge portions of the split ring and a driver portion for engaging an end thereof to facilitate axial rotation thereof on the first tubular member.

BACKGROUND OF THE INVENTION 
The invention relates generally to an improved pipe coupling assembly and, 
more particularly, to an easily assembled and disassembled pipe coupling 
assembly. 
Known methods for connecting a length of metal pipe or tubing to valves or 
pipe fittings such as elbows and tees include the use of threaded 
connectors, soldering, compression fitting, flaring and welding. 
Non-metallic pipe, such as thermoplastic pipe, may also be joined by 
adhesives. 
These methods are all subject to various drawbacks. Methods calling for the 
application of heat or force can be awkward and time consuming to practice 
in cramped and inaccessible areas, for example, areas in which residential 
plumbing is typically located. Soldering, welding and the like require the 
attention of a skilled worker using special tools to produce a good 
connection. Moreover, it is often difficult and time consuming to 
disconnect a length of pipe from a fitting once they have been joined, and 
it is often not possible to disassemble the joint without damaging the 
pipe or the fitting to such an extent that they cannot later be rejoined. 
Acceptable pipe joints are more difficult to make when the pipe is to carry 
a fluid under pressure. Even where threaded pipe and threaded connectors 
are used, greater skill is required to produce a strong and leakproof seal 
which will withstand the pressure rating of the pipe being joined. For 
proper sealing under pressure, washers or O-rings are often included in 
the joint. If the washer and pipe are made of dissimilar metals, they will 
sometimes undergo electrolysis in the presence of moisture in the joint or 
water and chemical agents flowing through the pipe. Electrolytic action 
leads to degradation of the washer, which can eventually cause the joint 
to leak and loosen the locking action of lock washers. 
Some of the aforementioned drawbacks are overcome by the use of plastic 
pipe joined by adhesive. But plastic pipe is difficult to connect directly 
to metal valve fittings without special adaptors. Moreover, once sealed 
with adhesive, prior plastic pipe joints cannot be readily undone. 
Disclosed in U.S. patent application Ser. No. 07/944,373, now U.S. Pat. 
No. 5,328,215, is an improved coupling assembly that is illustrated in 
FIGS. 1-9. A pipe coupling assembly 11 includes an inner first tubular 
member 12 and an outer receiving tubular member 13. The tubular member 12 
generally will be a length of pipe or tubing such as commonly employed for 
the delivery of fluids. The embracing tubular member 13 will generally 
form a part of a pipe fitting, such as an elbow, tee, or the like, or will 
form a part of some other component of a piping system, such as a valve. 
The receiving tubular member 13 includes an inner portion 14, an outer 
portion 15 and an end portion 16 with a radially inwardly directed rim 18 
that defines a circular opening 17 and an inwardly directed shoulder 19. 
Defined by the inner portion 14 of the receiving tubular member 13 is an 
inner bore 21 dimensioned to snugly receive the outer surface of the first 
tubular member 12. The outer portion 15 of the receiving tubular member 13 
defines an annular cavity 22 intercepting the inner bore 21 and projecting 
radially outwardly therefrom. Forming the annular cavity 22 is a 
cylindrical wall portion 24 and an annular tapered wall portion 25 joining 
the cylindrical wall portion 24 and the shoulder 19 surrounding the 
opening 17. An annular gap 27 is formed between the first tubular member 
12 and the rim 17 which has a diameter larger than the outer surface 
thereof. Defining an annular shoulder 28 on the receiving tubular member 
13 is a counterbore 29. An annular rib 31 on the receiving tubular member 
13 projects inwardly from the cylindrical portion 24 and separates the 
cavity 22 into longitudinally separated cavity portions 32 and 33. 
Projecting inwardly from the cylindrical wall portion 24 in the cavity 
portion 32 is a longitudinally disposed ridge 34. 
The pipe coupling assembly 11 also includes a split lock ring 35 disposed 
in the cavity portion 32, a sealing member 36 such as a resilient O-ring 
disposed in the cavity portion 33, and a split auxiliary ring 37 disposed 
in the cavity portion between the lock ring 35 and the annular rib 31. 
The lock ring 35 is made from a material suitable to establish a good 
spring characteristic. As shown in FIGS. 3-5, the lock ring 35 has a 
circular cross-section, an outer circumferential surface portion 41 of 
diameter D less than the diameter of the adjacent cylindrical wall portion 
24, and an inner circumferential surface portion 42 of diameter d less 
than the outer diameter of the first tubular member 12. Cut in the inner 
surface portion 42 is a circumferential groove 44 formed by one wall 43 
oriented perpendicular to an outer surface 45 of the first tubular member 
12, and another wall 47 extending between the outer surface of the ring 35 
and the one wall 43 and oriented perpendicular thereto. The another wall 
47 extends from the one wall 44 toward the opening 17 in the tubular 
member 13. Formed by the periphery of the one wall 43 is a circumferential 
knife edge 48 extending parallel to the outer surface 45 of the first 
tubular member 12. First and second ends 51, 52 of the lock ring 35 
straddle a split therein and, as shown in FIG. 3, the second end 52 is 
axially displaced from the first end 51 which is circumferentially aligned 
with the major portion of the ring 35. 
During assembly of the coupling 11, the first tubular member 12 is inserted 
through the opening 17 in the receiving tubular member 13 until an inner 
end 68 of the member 12 engages the annular shoulder 28 as shown in FIG. 
4. As the first tubular member 12 moves through the annular cavity 22, its 
external surface engages the knife edge inner surface 48 of the lock ring 
35 expanding it outwardly into the cavity portion 32 of the annular cavity 
22. However, since the outer diameter D of the lock ring 35 is less than 
that of the cylindrical wall portion 24, inward axial movement of the 
first tubular member 12 is not restricted. In addition, the auxiliary ring 
37 is compressed between the cylindrical surface portion 24 and the outer 
surface of the first tubular member 12 which outer surface is scored by 
the longitudinal projecting edges 64. Because of this penetration of the 
first tubular member 12 by the edges 64 on the compressed auxiliary ring 
37, rotation of the first member 12 within the receiving member 13 is 
prevented. A tapered annular transitional surface 69 between the 
cylindrical surface portion 24 and the inner bore 21 accommodates 
longitudinal migration of the sealing member 36 so as to prevent damage 
thereto during insertion of the first tubular member 12 as shown in FIG. 
8. 
After full insertion, the first tubular member 12 is partially withdrawn to 
produce a longitudinal separation movement relative to the receiving 
tubular member 13. During that movement, the lock ring 35 is forced 
longitudinally outwardly in the annular cavity 22 and tightly compressed 
therein between the shoulder stop 19, the tapered wall portion 25 and the 
outer surface of the first tubular member 12 as shown in FIG. 9. Because 
of the penetration of the outer surface of the first tubular member 12 by 
the knife edge 48 on the lock ring 35, further relative longitudinal 
movement between the member 12 and the receiving tubular member 13 is 
prevented. In addition, the second end 52 of the lock ring 35 is forced 
into circumferential alignment with the first end 51 creating an axially 
directed force that biases the member 12 inwardly in the member 13. Fluid 
pressure within the coupling 11 exerts on the first member 12 a 
longitudinally outwardly directed force F that is transferred by the 
tapered wall portion 25 radially inwardly on the lock ring 35. 
Consequently, the knife edge 48 is driven further into the outer surface 
of the first member 12 and enhancing the securement thereof to the 
receiving member 13. With the parts in the relative positions shown in 
FIG. 9, the O-ring 36 is engaged between the cylindrical surface portion 
24 and the outer surface of the first tubular member 12 to create a fluid 
tight seal therebetween. The annular rib 31 prevents damage of the annular 
sealing member 36 by the teeth 63 on the auxiliary ring 37. 
The coupling assembly 11 alleviates many of the above noted problems. 
However, the operational characteristics of the coupling 11 are not 
suitable for all applications. 
The object of this invention, therefore, is to provide an improved high 
pressure pipe coupling assembly that can be easily assembled and 
disassembled by unskilled workers. 
SUMMARY OF THE INVENTION 
The invention is a coupling assembly including a receiving tubular member 
defining an opening for receiving a first tubular member, the receiving 
tubular member having an inner portion defining an inner bore dimensioned 
to receive one end of the first member and an outer portion defining an 
internal annular cavity intersecting the inner bore and projecting 
radially outwardly therefrom, the annular cavity comprising an annular 
tapered wall portion tapered radially inwardly and projecting 
longitudinally toward the opening; and a split lock ring formed from 
spring material and disposed in the annular cavity between the first 
tubular member and the receiving tubular member, the lock ring having an 
outer circumferential surface portion adapted to engage the tapered wall 
portion and an inner circumferential surface portion adapted to engage an 
external wall portion of the first tubular member, the lock ring being 
adapted to expand circumferentially into the annular cavity during 
insertion of said first tubular member into the receiving tubular member 
and to be compressed between the tapered wall portion and the external 
wall portion in response to relative longitudinal separating movement 
between the first tubular member and the receiving tubular member and, the 
inner circumferential surface portion defining first and second 
substantially parallel, spaced apart, circumferentially extending knife 
edge means. Also included is an annular sealing member disposed in the 
annular cavity between said lock ring and the inner bore, the sealing 
member dimensioned to be engaged between said first tubular member and the 
receiving tubular member. Under high pressure conditions both knife edge 
means penetrate the external wall portion so as to prevent longitudinal 
movement of the first tubular member relative to the receiving tubular 
member. 
According to one feature of the invention, each knife edge means is a 
circumferential edge formed by, respectively, first and second 
circumferential grooves in the lock ring. The circumferential knife edges 
penetrate the first tubular member to prevent relative movement thereof. 
According to other features of the invention the first groove defines one 
wall terminated by the first circumferential edge and oriented 
substantially perpendicular to the external wall portion and the second 
groove defines a second wall terminated by the second circumferential edge 
and oriented substantially perpendicular to the external wall portion. The 
substantially perpendicular wall portions form effective movement 
restricting knife edges. 
According to yet another feature of the invention, the lock ring has first 
and second ends normally axially displaced, and the first and second ends 
are forced into substantial alignment in response to compression of the 
lock ring between the tapered wall portion and the external wall portion. 
With its ends aligned, the lock ring creates a force biasing the first 
tubular member into the receiving tubular member. 
According to yet another feature of the invention, the split ring has an 
inner diameter less than the outer diameter of the first tubular member. 
This feature assures penetration of the first tubular member by the knife 
edges. 
According to a further feature of the invention, at least one of the knife 
edge means defines a plurality of circumferentially spaced apart slots 
that form circumferentially distributed teeth on the knife edge means. The 
teeth engage the first tubular member to prevent therebetween relative 
rotational movement that would excessively score the outer surface. 
The invention also encompasses a coupling including an externally threaded 
receiving tubular member defining an opening adapted to receive a first 
tubular member; the receiving tubular member having an inner portion 
defining an inner bore dimensioned to receive one end of the first tubular 
member; and an outer portion defining an internal annular cavity 
intersecting the inner bore and projecting radially outwardly therefrom, 
the annular cavity comprising an annular tapered wall portion tapered 
radially inwardly and projecting longitudinally toward the opening; a 
split lock ring defining at least one circumferentially extending knife 
edge means for penetrating the external wall portion so as to prevent 
longitudinal movement of the first tubular member relative to the 
receiving tubular member; an annular sealing member disposed in the 
annular cavity between the lock ring and the inner bore; and an outer 
tubular coupling member having an internally threaded portion for engaging 
the receiving member and an annular reentrant portion received by the 
annular cavity and defining the outwardly tapered wall portion for 
engaging the lock ring. 
According to one feature of the immediately above invention, the inner bore 
terminates with an annular groove facing the opening, partially formed by 
the inner bore, and dimensioned to receive the one end, the receiving 
member is plastic, and the first tubular member comprises radially spaced 
apart plastic laminations separated by a metal lamination. The plastic 
laminations become swedged into the groove to form a seal around the metal 
lamination. 
The invention further encompasses a disengagement tool for use with the 
above assemblies and including a plurality of arcuately shaped parts, each 
having an inner surface conforming to the outer surface of the first 
tubular member and adapted for engagement therewith in a juxtaposed 
relationship thereabout to the parts being adapted for sliding movement on 
the first tubular member and having actuator end portions adapted to be 
pushed through the opening into the annular cavity and into forcible 
engagement with the lock ring so as to cause circumferential expansion 
thereof. In addition, at least one of the parts has a driver portion for 
engaging the first end of the lock ring and causes rotation thereof in 
response to rotation of the one part on the outer surface of the first 
tubular member. Rotation of the lock ring releases it from annular burrs 
formed in the first tubular member by the penetrating knife edges and 
subsequent circumferential expansion of the lock ring eliminates 
engagement between the knife edges and the first tubular member to permit 
removal thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A coupling assembly 71 shown in FIGS. 10-14 is similar to the prior 
coupling assembly 11 shown in FIGS. 1-9 and identical parts of the two 
assemblies have been given the same reference numerals. Eliminated from 
the coupling assembly 71 is the auxiliary ring 37 used in the prior 
coupling assembly 11 and the split lock ring 35 therein is replaced in the 
assembly 71 by a split lock ring 72. Again, the lock ring 72 is made from 
a material suitable to establish a good spring characteristic. 
The lock ring 72 has a circular cross section and circumferential 
dimensions identical to those described above for the lock ring 35 of 
coupling assembly 11. Cut into an inner surface portion 73 of the ring 72 
is a first circumferential groove 74 formed by a first wall 75 oriented 
perpendicular to the outer surface 45 of the first tubular member 12. The 
periphery of the first wall 75 forms a first circumferential knife edge 76 
extending parallel to the outer surface 45 of the first tubular member 12. 
As shown in FIGS. 11-13, a plurality of circumferentially distributed 
slots 77 are cut into the inwardly directed circumferentially formed knife 
edge 76 on the split ring 72. The slots 77 form circumferentially 
distributed teeth 80 on the knife edge 76. 
Also cut into the ring 72 adjacent to the first groove 74 is a second 
circumferential groove 78 including a second wall 79 extending 
perpendicular to the outer surface 45 of the first tubular member 12 and 
terminating with a second circumferential knife edge 81 spaced from and 
parallel to the first knife edge 76. The second wall 79 intersects a third 
wall 82 of the first groove 74. As described for the lock ring 35, the 
lock ring 72 has first and second axially displaced ends 51, 52 that 
straddle a split as shown in FIG. 11. 
The coupling assembly 71 is assembled in the same manner as described above 
for the coupling assembly 11. As the first tubular member 12 is partially 
withdrawn from the receiving tubular member 13, the lock ring 72 is forced 
longitudinally outwardly in the annular cavity 22 producing penetration of 
the outer surface 45 of the first tubular member 12 by the first knife 
edge 76 as shown in FIG. 10. Because of this engagement between the first 
knife edge 76 and the first tubular member 12 and the wedging of the lock 
ring 72 by the tapered wall portion 25, further relative longitudinal 
movement between the members 12 and 13 is prevented. 
In the event of a significant increase in fluid pressure within the tubular 
members 12, 13, the increased force exerted between the engaged members 12 
and 72 can induce clockwise twisting of the ring 72 and further wedging 
movement thereof along the tapered wall portion 25 of the annular cavity 
22 and into engagement with the shoulder 19 as shown in FIG. 14. Such 
twisting of the ring 72 causes the second knife edge 81 to also penetrate 
that outer surface 45 of the first tubular member 12. With both the first 
and second longitudinally spaced apart knife edges 76, 81 engaged with the 
external surface 45, additional separating movement between the first 
tubular member 12 and the second tubular member 13 and further twisting of 
the ring 72 are prevented. In addition, engagement between the outer 
surface 45 and the teeth 80 insures that any induced rotation of the first 
tubular member 12 within the receiving tubular member 13 will produce 
sympathetic rotation of the lock ring 72. Thus, excessive scoring of the 
outer surface 45 by the knife edges 76, 81 is prevented. 
Illustrated in FIGS. 15 and 16 is another coupling assembly 85 including an 
inner first tubular member 86, an outer receiving plastic tubular member 
87 and an outer tubular coupling member 88. The receiving tubular member 
87 includes an inner portion 89 and an outer portion 91 and an externally 
threaded outer surface 92. Defined by the inner portion 89 is an inner 
bore 93 dimensioned to snugly receive the outer surface of the first 
tubular member 86. Also defined by the inner portion 89 of the receiving 
tubular member 87 is an annular groove 96 partially formed by the inner 
bore 93 and facing an opening 96 for receiving the first tubular member 
86. The annular groove 95 has a radially inwardly and longitudinally 
outwardly tapered surface 97. Defined by the outer portion 91 of the 
receiving tubular member 87 is an radially outwardly opening annular 
cavity 99 that intersects the inner bore 93. 
The tubular coupling member 88 has an internally threaded portion 101 for 
engaging the externally threaded portion 92 of the receiving member 87. 
Formed at one end of the coupling member 88 is an annular reentrant 
portion 102 that is dimensioned to enter the annular cavity 99 in the 
receiving member 88. The reentrant portion 102 has a inwardly tapered wall 
portion 105 projecting radially inwardly and toward the opening 96. 
Preferably, the first tubular member 86 is composed of an outer plastic 
lamination 107, an inner plastic lamination 108, and an intermediate metal 
lamination 109 between the inner and outer plastic laminations 107, 108. 
Straddled by a plastic spacer ring 111 in the annular cavity 99 is an 
internal O-ring 112 and a split lock ring 113 that is substantially 
identical to the split lock ring 35 described above and shown in FIGS. 3 
and 4. Again, the ring 113 is a split ring and dimensioned for operation 
in the same manner as described above for the split ring 35. 
During assembly of the coupling assembly 85 the first tubular member is 
inserted through the opening 96 in the receiving tubular member 87 and 
into engagement with the tapered surface 97 of the annular groove 95 as 
shown in FIG. 15. Next,the coupling member 88 is rotated inwardly on the 
receiving member 87 to produce movement of the reentrant portion 102 into 
the annular cavity 99. Engagement between the tapered surface 105 and the 
split ring 113 causes penetration of the outer lamination 107 of the first 
tubular member 86 by a knife edge 115 on the split ring 113. Because of 
the engagement between the ring 113 and the first outer lamination 107, 
further inward movement of the reentrant portion 102 forces an inner end 
121 of the first tubular member 86 into the annular groove 95 in the 
receiving member 87. That action swedges the inner end 121 of the first 
tubular member 86 against the tapered surface 97 and produces between the 
engaging plastic surfaces of the annular groove 95 and the inner 
lamination 108 a high force creating a fluid tight seal. That seal 
prevents contact between a fluid within the tubular member 86 and the 
metal lamination 109 to insure against corrosion thereof. In addition, the 
inward movement of the reentrant portion 102 forces the spacer ring 111 
inwardly compressing the O-ring 112 to create a secondary seal between the 
O-ring 112 and the fixed outer lamination 107 in the event of the leakage 
through the seal between the inner lamination 108 and the annular groove 
95 of the receiving tubular member 87. 
Disassembly of the coupling 71 requires the use of a disengagement tool 121 
shown in FIGS. 17-19. The disengagement tool 121 consists of first and 
second identically shaped arcuate parts 122, 123, respectively. Each of 
the parts 122, 123 has a longitudinally extending inner cylindrical 
surface 124 conforming to the outer surface of the first tubular member 
12. One end 125 of the part 72 is connected to one end 126 of the part 123 
by a flexible connection portion 127 that permits relative pivotal 
movement therebetween as shown by dashed lines in FIG. 18. When positioned 
on the outer surface of a first tubular member 12 actuator end portions 
129 of the parts 122, 123, form a composite tube 130 having an outwardly 
facing, annular tapered surface 131. Extending radially outwardly from 
each of the parts 122, 123 is a flange portion 132, 133, respectively. A 
driver portion 136 projects outwardly from the end 129 of the part 122. 
To disassemble the coupling 71, the opposite ends 125, 126 of the parts 
122, 123, respectively, are separated as shown in FIG. 19 allowing the 
tool 71 to be positioned around the tubular member 12 with the surfaces 
124 engaging the outer surface 45 thereof. Next, the flange portions 132, 
133 of the parts 122, 123 are pushed to produce sliding movement of the 
cylindrical surfaces 124 on the outer surface 45 of the first tubular 
member 12. That sliding movement is continued to move the annular actuator 
end 129 of the composite tube 130 through the annular gap 27 until the 
driver portion 136 engages the end 51 of the lock ring 72 as shown in FIG. 
19. One revolution of the parts 122, 123 on the surface 45, rotates the 
lock ring 72 out of the burrs 140, 141 created by the knife edges 76, 81 
and shown in FIG. 20. Next, the tool 121 is pushed inwardly until the 
flange portions 132, 133 engage the outer end 16 of the receiving tubular 
member 13. During the inward movement of the actuator end portions 129, 
the annular tapered surfaces 131 engage and force the lock ring 72 into an 
inward position as shown in FIG. 19. Movement into that inner portion of 
the cavity 22 allows the lock ring 72 to expand circumferentially in 
response to the radially outwardly directed force produced by the tapered 
surfaces 131. The circumferential expansion eliminates engagement between 
the lock ring 72 and the outer surface 45 of the first tubular member 12. 
Accordingly, the first tubular member 12 can be withdrawn easily from the 
receiving tubular member 13. 
Obviously, many modifications and variations of the present invention are 
possible in light of the above teachings. It is to be understood, 
therefore, that the invention can be practiced otherwise than as 
specifically described.