Fluid conduit coupling apparatus

A quick connect coupling for fluid conduits having an outer cylindrical member and an inner conduit fitted within the outer cylindrical member including a continuous circular gripper ring seated in the outer cylindrical member and having radially inward gripper teeth bent axially forward toward the outer cylindrical member in a generally conical plane, each tooth has a twist in a common direction whereby the inner conduit can be slid into the gripper ring but removed from the gripper ring only by unscrewing from the gripper ring.

DESCRIPTION TECHNICAL FIELD 
This invention pertains to quick connect fluid coupling apparatus in which 
the one fluid conduit is connected in fluid tight arrangement to another 
fluid conduit for use in couplings, valves and the like. More 
particularly, the invention is directed to an improved gripper ring which 
allows the one tubular conduit to be slidably engaged within the other 
fluid conduit, but allows release of the first fluid coupling only by 
threading outwardly from the second tubular conduit. 
DESCRIPTION OF THE PRIOR ART 
U.S. Pat. No. 4,390,159 describes various embodiments of a valve and 
tubular conduit coupling device in which a split gripper ring having 
radially inner sharpened teeth will slidably receive one tubular conduit 
when inserted in one axial direction, but will lock or hold that tubular 
conduit from retraction in a straight line rearward axial direction. 
Release of the tubular conduit, however, can be accomplished by threading 
the inserted tubular conduit outwardly relative to the gripper ring. This 
type of coupling device has the advantage of being connected in fluid 
tight arrangement without the use of tools and with a minimum of time 
expended. While it holds the inserted tubular conduit tightly in fluid 
tight gripping arrangement, it offers the additional advantage of allowing 
the inserted tubular coupling to be threadably removed without destroying 
the gripper teeth. Thus, if the tubular conduit should become cracked or 
otherwise needs servicing, it is not necessary to destroy the whole 
coupling apparatus, but rather necessary only to unscrew the inserted 
tubular coupling and replace it with a new tubular coupling. In the 
alternative, the conduit could be removed and reused, if desired. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a low cost, easily assembled, 
tubular coupling. 
It is another object of this invention to provide an improved gripper ring 
for a tubular coupling. 
Basically, the invention includes an inner cylindrical surface in a first 
tubular member, an outer cylindrical surface slightly smaller in diameter 
than the inner cylindrical surface of the first tubular member in a second 
tubular member, means sealingly engaging the inner and outer cylindrical 
surfaces of said first and second tubular members, and gripping apparatus 
held in said inner cylindrical surface of said first tubular member and 
releasably locked to the outer cylindrical surface of said second tubular 
member, said gripping apparatus having a plurality of radially inner 
circumferentially spaced teeth having radially inner sharp edges, said 
teeth extending radially inward and axially forward, along a generally 
conical plane and each tooth having a slight rotational twist in a common 
direction whereby the second tubular member can be slid past said teeth 
when inserted axially in a direction of convergence of said conical plane 
of the teeth, but can be removed without destruction of said teeth only by 
unscrewing the second tubular member relative to said teeth. 
In one embodiment, the gripping apparatus is provided within a valve body. 
In additional embodiments, the gripping apparatus is provided within 
couplings for joining two tubular conduits or joining elbows and the like.

DETAILED DESCRIPTION OF THE INVENTION 
As best shown in FIGS. 2 and 3, a coupling 10 includes a cylindrical 
housing 12 having an axial bore defining an inner cylindrical surface 14 
and terminating in an inner shoulder 16. Seated against the inner shoulder 
is an improved gripper ring 18 having a plurality of radially inward teeth 
20 terminating in sharp edges 21. 
As best shown in FIGS. 2 and 4, the gripper ring is a continuous 
cylindrical ring with the teeth 20 being bent axially forward in a 
generally converging conical plane at an angle of approximately 30.degree. 
as shown by the letter "B" in FIG. 4. Each tooth is also given an 
additional twist in a common direction such that the forward most edge of 
the tooth is bent at an angle of about 33.degree. as shown by the 
reference character "A" in FIG. 4. This conical and twist arrangement of 
the teeth allows a tubular conduit to be slid past the sharp edges of the 
ends of the teeth 21, when the tubular conduit is being inserted to the 
left in FIGS. 2 and 4. The teeth will bite into the tubular conduit, 
however, if the tubular conduit is retracted in a straight line in FIGS. 2 
and 4. Thus, the tubular conduit is held tightly within the inner 
cylindrical surface 14. However, the tubular conduit can be removed by 
threading the tubular conduit outwardly with the teeth scribing a line in 
the material of the conduit. Thus, the conduit can be advantageously 
removed if necessary by unscrewing one of the conduits relative to the 
other, but in normal operation will remain locked together by the teeth of 
the gripper ring. The solid gripper ring is to be contrasted with the 
gripper ring shown in U.S. Pat. No. 4,390,159. The scope of that patent 
was intended to cover any type of gripper ring, solid or discontinuous 
allowing unscrewing of the conduit, with this embodiment of this 
invention, however, being an improvement in providing the same kind of 
spiral removal, but doing it with a twist in the teeth of the gripper 
ring. 
A notch 17 in the gripper ring fits over a flange 27 in the coupling to 
prevent rotation of the gripper ring. 
In addition to the gripper ring 18, a bushing 24 is positioned against the 
gripper ring to hold it firmly against the inner shoulder 16. An O-ring 
seal 26 is rested against the bushing 16. An end bushing 28 is then 
snapped into the tubular housing 12 and held by sonic welding or other 
means for securing the end bushing to the housing 12. The inner end 30 of 
the end bushing 28 rests against the O-ring seal and compresses the seal 
so that it expands radially, outwardly and inwardly to form a fluid-tight 
seal between an outer cylindrical surface 31 on an inner-tubular conduit 
32 and the inner cylindrical 14 of the housing 12. A sonic weld is shown 
at 38. 
FIG. 3 shows the coupling of FIG. 2 in a sectional view with like reference 
numerals being illustrated. 
As shown in FIG. 1, the coupling arrangement can be embodied in a valve 
body 40 having a radially outer cylindrical housing 42 terminating in the 
shoulder 16. The remaining parts are as illustrated in FIGS. 1 and 1A and 
include the O-ring seal 26, the gripper ring 18 and the bushing 24 held in 
by the end bushing 28. A notch 25 engages a flange 27 to prevent rotation 
of the bushing. 
The valve body of FIG. 1, however, also includes a valve stem 50 
terminating at one end in an actuator 52 and a valve member 54. The valve 
member has an O-ring 56 that rests on a valve seat 58. A second port 60 is 
joined to the valve body. The valve actuator 52 is provided with an inner 
surface 70 that rides over a detent 72 to snap the valve in an open 
position holding the valve member 54 open. A second O-ring 76 seals the 
valve stem against the valve body to prevent fluid moving out around the 
valve stem. 
While the preferred embodiments of the invention have been illustrated and 
described, it should be understood that variations will be apparent to one 
skilled in the art without departing from the principles herein. 
Accordingly, the invention is not to be limited to the specific 
embodiments illustrated in the drawings.