Quick disconnect ball joint coupling

A novel quick disconnect ball joint coupling which utilizes as a misalignment ball locking mechanism, a combination of a plurality of locking balls and a locking sleeve. The locking sleeve provides an annular race or groove for receiving the locking balls, thereby obviating the high stress point-to-point contact problem associated with prior art locking ball techniques, but still provides the advantage of high speed, low torque rotation available with the use of such locking balls. More specifically, in the present invention, the locking balls do not come in direct contact with the misalignment ball, but are instead positioned in an annular groove on the exterior surface of the locking sleeve between the locking sleeve and the quick disconnect releasing sleeve. The locking sleeve is preferably spring loaded so that upon rotation, the locking sleeve remains stable with respect to the misalignment ball, thereby gaining the benefits of the low friction of a ball and race configuration during rotation. On the other hand, because the locking balls do not directly interface with the misalignment ball, but instead indirectly interface through the much larger surface area of the locking sleeve, even extremely high fluid pressures will not produce the contact stress levels found in the prior art. Accordingly, the present invention provides a novel combination of locking balls and a locking sleeve which affords low point contact stress levels even at high fluid pressures and low torque requirements for rotation.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to fluid-tight quick disconnect 
couplings and more specifically to a quick disconnect ball joint coupling 
in which the conduits through which fluid flows to each half of the 
coupling may be misaligned and/or rotated when the coupling is engaged. 
2. Prior Art 
Quick disconnect couplings which must accommodate misaligned conduits are 
commonly provided in the form of a combined quick disconnect and ball 
joint. The ball joint coupling is typically held in engagement by means of 
a large misalignment ball which is locked by a plurality of small locking 
balls or by a sleeve which has an arched interior surface compatible with 
the diameter of the misalignment ball. While both of these prior art ball 
joint configurations permit both misalignment and rotation, they suffer 
from a number of inherent disadvantages which can preclude their 
usefulness. By way of example, those prior art combined quick disconnect 
and ball joint couplings in which the misalignment ball is held in place 
by a plurality of locking balls can, at particularly high pressure levels, 
result in the smaller locking balls being embedded into the surface of the 
larger misalignment ball. On the other hand, some prior art combined quick 
disconnect and ball joint couplings utilize a sleeve instead of locking 
balls to secure the misalignment ball in place while distributing the 
locking contact stress over a much wider surface area. However, these 
prior art couplings suffer the disadvantage of substantially increased 
rotational friction, thereby requiring a very high torque to rotate the 
coupling at high fluid pressure levels. There is therefore an existing 
need for an improved quick disconnect ball joint coupling in which the 
point of contact stress levels are reduced, but which at the same time 
requires only a relatively low torque to enable relative rotation between 
the male and female members of the quick disconnect. 
Prior art relevant to the present invention includes the following United 
States patents: 
U.S. Pat. No. 3,420,497 to Wilcox is directed to a misalignable fluid quick 
disconnect coupling. A nipple portion terminates in a bulbous spherical 
section which when captured within the nipple-receiving passage allows 
relative angular displacement of the nipple relative to the coupling 
housing. Leakage of fluid is prevented by an O-ring and a seal ring, while 
the spherical end portion of the nipple is retained within the passage by 
a plurality of locking balls, which are displaceable within the passage by 
the axial displacement of a sleeve. 
U.S. Pat. No. 2,848,255 to Klein et al is directed to a lubricant fitting 
for coupling with a grease fitting. The lubricant-receiving fitting has a 
spherical bulbous head which is received within a cylindrical socket of 
the coupler body. The coupler is locked on the head of the fitting by the 
split ring which rides past the collar of the head, but sufficient axial 
force can be applied to quickly separate the two. 
U.S. Pat. No. 4,269,226 to Allread is directed to a breakaway fluid 
coupling separable by pivotal movement of one coupling part relative to 
the other. The male coupling part is provided with a spherical segment 
sealing surface and a spherical segment locking surface which allows 
pivotal movement of the male portion relative to the female coupling 
portion. However, if in addition to the swivel force, a tension force is 
applied, the coupling will separate. 
U.S. Pat. No. 3,997,197 to Marsh et al is directed to a ball and socket 
pipe coupling. The coupling member is provided with a spherically-shaped 
ball-like enlarged portion which is received within the spherical shaped 
socket portion of coupling member. The ball and socket arrangement allows 
the central axes of the coupling members to be inclined at an angle 
relative to each other while still maintaining a fluid-tight connection. A 
plurality of jaws or cam members are circumferentially disposed about a 
housing and pivotably movable to permit a socket of the housing to freely 
receive the spherically-shaped forward side of the enlarged portion for 
making engagement therewith. 
U.S. Pat. No. 3,450,421 to Hatwell Jr. is directed to a combined flexible 
joint and remotely connectible and disconnectible union. The ball 
connector includes a tubular conduit having a ball member for releasable 
locking engagement with the ball housing member coupled to a second 
tubular conduit. When the ball is locked within the coupling, the conduits 
are free to pivot 10 degrees in any direction while a quick disconnect 
operation is performed by displacing a bearing ring. 
U.S. Pat. No. 4,703,958 to Fremy is directed to a quick disconnect type 
coupling having a radially acting bolt. The balls act against a 
cylindrical bolt for locking the male member therein. 
U.S. Pat. No. 3,606,393 to Huntsinger et al is directed to a pipe 
connection for underwater well head equipment. Of interest here, is the 
split retaining ring adapted to engage an external pin groove, and 
includes a spring bias provided by the coil compression spring which acts 
against a pin. 
U.S. Pat. No. 4,413,846 to Oetiker is directed to a hose coupling with a 
latching mechanism. As shown in FIG. 1, the coupling includes a latching 
member and a safety locking member, both having a relatively flat 
configuration which engage the male coupling member under spring bias. 
U.S. Pat. No. 3,944,263 to Arnold is directed to a dynamic pipe coupling 
having pressure operated seals. The socket portion of the ball type 
coupling includes three annular seals, each being biased against the ball 
of the mating portion by means of fluid pressure, as opposed to spring 
bias balls. 
U.S. Pat. No. 2,550,536 to Delano, Jr. et al is directed to a high-pressure 
ball and socket pipe joint. Of interest here, is the flat ring which is 
biased by a plurality of spring washers. However, the flat ring is 
utilized for applying pressure to the packing rings, as opposed to 
retaining the ball member within the socket member. 
SUMMARY OF THE INVENTION 
The present invention comprises a combined ball joint and quick disconnect 
coupling which is particularly advantageous in high pressure fluid 
applications. The present invention permits locking and rotation to be 
controlled by means of locking balls while angular misalignment is 
controlled by a sleeve designed to accept the misalignment ball diameter. 
This novel combination of locking balls and a sleeve affords low torque 
rotation, thereby allowing high speed operation, while at the same time, 
providing the significant advantage of a large surface area contact for 
reducing stress levels at the point of contact with the misalignment ball. 
In addition, the novel combination of locking balls and locking sleeve in 
the present invention provides an advantageous redundancy in that if that 
the locking ball mechanism should fail, the sleeve that is also provided 
would still enable rotation, although at a higher torque. 
More specifically, in the present invention, the locking balls do not come 
in direct contact with the misalignment ball, but are instead positioned 
in an annular groove on the exterior surface of the locking sleeve between 
the locking sleeve and the quick disconnect releasing sleeve. The locking 
sleeve is preferably spring loaded so that upon rotation, the locking 
sleeve remains stable with respect to the misalignment ball, thereby 
gaining the benefits of the low friction of a ball and race configuration 
during rotation. This feature is particularly beneficial during low fluid 
media pressure rotation. On the other hand, because the locking balls do 
not directly interface with the misalignment ball but instead indirectly 
interface through the much larger surface area of the locking sleeve, even 
extremely high fluid pressures will not produce the contact stress levels 
found in the prior art. Accordingly, the present invention provides a 
novel combination of locking balls and a locking sleeve which affords low 
point contact stress levels even at high fluid pressures and low torque 
requirements for rotation. 
OBJECTS OF THE INVENTION 
It is therefore a principal object of the present invention to provide a 
combined quick disconnect and ball joint coupling which is especially 
suited for use in high pressure fluid applications and which is designed 
to provide relatively low stress contact point locking of a misalignment 
ball while simultaneously providing a relatively low torque rotation 
capability. 
It is an additional object of the present invention to provide a 
misalignable quick disconnect coupling of the type which uses a 
misalignment ball held in place when coupled by a combination of a locking 
sleeve and a plurality of locking balls to facilitate low stress contact 
point engagement of the misalignment ball and simultaneously to facilitate 
low torque rotation capability of the female member of the coupling 
relative to the male member of the coupling. 
It is still an additional object of the present invention to provide a high 
pressure capability misalignable quick disconnect coupling capable of high 
speed rotation torque despite a high contact surface area between the 
misalignment ball of the coupling and the locking mechanism as a result of 
a combination of an annularly shaped locking mechanism having grooves for 
receiving a plurality of locking balls, the former providing control of 
misalignment and the latter providing control of rotation.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
In order to best understand the design and advantages of the present 
invention, reference will first be made to FIGS. 1 and 2 which show two 
prior art configurations of combined quick disconnect and ball joint 
couplings. More specifically, referring first to FIG. 1, it will be seen 
that a first exemplary prior art quick disconnect 10 comprises a female 
member 12 and a male member or nipple 14. Male member 14 provides a 
misalignment ball 16 which, when members 12 and 14 are interconnected, is 
held in place within a dimensionally compatible engaging surface 18 of 
female member 12. A locking engagement between misalignment ball 16 and 
engaging surface 18 is provided by a plurality of locking balls 20, which 
are in direct contact with the exterior surface of misalignment ball 16. 
Female member 12 is provided with a threaded portion 13 which permits 
connection to a conduit (not shown). Similarly, male member 14 is provided 
with a threaded portion 15 which permits connection of the male member to 
a conduit (also not shown). A stop flange 17 may be provided so that there 
is no inadvertent interference with the interconnection and disconnection 
between female member 12 and male member 14. 
Disconnection or release of the misalignment ball 16 from the engaging 
surface 18 may be effected by a releasing sleeve 22 which, when moved 
axially from right to left in FIG. 1 against the pressure of a spring 24, 
permits the locking balls 20 to separate from the contacting surface of 
misalignment ball 16, thereby allowing separation of the male member 14 
from the female member 12. An O-ring 26 provides a fluid-tight seal 
between the misalignment ball 16 and the engaging surface 18 when the male 
member 14 and female member 12 are interconnected in the manner shown in 
FIG. 1. 
The configuration of prior art quick disconnect ball joint coupling 10 of 
FIG. 1 is exemplary of a number such couplings such as the coupling 
disclosed in prior art patent 3,420,497 to Wilcox. It serves the desired 
general purpose of providing a quick disconnect which can accommodate a 
substantial degree of misalignment between the interconnected conduits and 
which also permits relative rotation between the male member and the 
female member thereof. Locking, angular misalignment and rotation are all 
controlled through the use of the small locking balls 20 placed around the 
larger misalignment ball 16. Unfortunately, the prior art design of FIG. 1 
is limited to very low fluid pressures due to the high stress loading at 
the ball-to-ball contact point. Thus for example the following formula may 
be used to calculate the stress at the point of contact between the 
locking balls 20 and the misalignment ball 16. 
##EQU1## 
S=Stress at point of contact, PSI. P=Load, LBs. 
E=Modulus of elasticity, PSI. 
D.sub.1 =Diameter of misalignment ball, IN. 
D.sub.2 =Diameter of locking ball, IN. 
##EQU2## 
Using the above noted formula, it will be seen that for a fluid pressure of 
20 PSIG a one inch diameter misalignment ball which is held in the coupled 
position by sixteen 1/8 inch diameter locking balls, results in a stress 
at the point of contact of approximately 154,000 PSI, when the sealing 
surface, that is the diameter of O-ring 26 is 1/2 inch. This level of 
contact point stress is acceptable for normal materials used in such quick 
disconnect ball joint couplings. Unfortunately however, if the fluid 
pressure is increased to say 8,000 PSIG, the stress increases to 1,134,000 
PSI. At this stress level, the smaller locking balls will be embedded into 
the surface of the larger misalignment ball, damaging the coupling and 
rendering it virtually useless for misalignment and rotation capabilities. 
The prior art alternative shown in FIG. 2 is one way of increasing the 
stress capability and therefore the high fluid pressure capability of such 
quick disconnect ball joint couplings. More specifically, as shown in FIG. 
2, a quick disconnect 30 comprises a female member 32 and a male member 
34, the latter terminating in a connecting or misalignment ball 36. 
Similarly, the female member 32 comprises an engaging surface 38 which is 
dimensionally compatible with the misalignment ball 36. As in the first 
prior art embodiment of FIG. 1, the female member is provided with a 
threaded portion 33, while the male member is provided with a threaded 
portion 35 and a stop flange 37. An O-ring 46 provides the same type of 
fluid sealing between the misalignment ball 36 and the engaging surface 38 
of female member 32 when the coupling is connected. 
However, unlike the first prior art configuration of FIG. 1, in the prior 
art configuration of FIG. 2 the misalignment ball 36 is held in place by a 
locking sleeve 40 which is, in turn, positioned in locking engagement with 
the misalignment ball 36 by a releasing sleeve 42 and a spring 44. Locking 
sleeve 40 is actually an annular segment of a spherical shell having an 
inner diameter which is dimensionally compatible with the outer diameter 
of misalignment ball 36. Consequently, unlike the prior art configuration 
of FIG. 1, the prior art configuration of FIG. 2 provides a substantially 
greater surface area contact between the locking mechanism, that is 
locking sleeve 40 and the sphere 36. The prior art configuration of FIG. 2 
is similar to those shown in U.S. Pat. No. 2,848,255 to Klein et al, U.S. 
Pat. No. 3,997,197 to Marsh et al and U.S. Pat. No. 4,298,219 to Amelink. 
Because this particular prior art configuration overcomes the 
point-to-point contact problem of the prior art configuration of FIG. 1, 
it has clearly a much higher fluid pressure capability. It allows locking, 
angular misalignment and rotation to be controlled through the use of the 
segmented sleeve 40 which is designed to accept the misalignment ball 
diameter. Unfortunately however, the rotational speed of the spin of the 
male member 34 relative to the female member 32 is limited and the torque 
required to produce such relative rotation is quite high due to the 
friction of the high surface area contact between the sleeve 40 and the 
misalignment ball 36. 
Consequently, in comparing the prior art configurations of FIG. 1 and 2, 
one can readily see that in the prior art of quick disconnect ball joint 
couplings, there is of necessity a choice to be made between high pressure 
performance and locking misalignment on the one hand and low torque 
rotation on the other. Therefore, when it is necessary to specify both 
high pressure misalignment capability and low torque high rotational speed 
capability, the prior art has unfortunately not provided a solution 
compatible with both such capabilities. Fortunately, the present invention 
provides a solution to this incompatability of the prior art. 
More specifically, as seen in FIG. 3, the quick disconnect 50 of the 
present invention comprises a female member 52 and a male member 54, the 
latter having a misalignment ball 56 of the same configuration disclosed 
and discussed previously in conjunction with FIGS. 1 and 2. Female member 
52 provides a threaded portion 53 while male member 54 provides a threaded 
portion 55 and a stop flange 57. A spherically shaped, dimensionally 
compatible engaging surface 58 is also provided as in the previous prior 
art configurations. However, the locking mechanism for retaining the 
misalignment ball 56 in engagement with the engaging surface 58 is quite 
distinct from both prior art configurations in FIG. 1 and 2 in that it 
comprises both a plurality of locking balls 60 and a locking sleeve 62, 
the latter being held in its position relative to misalignment ball 56 by 
a spring 64. Spring 64 is positioned in a spring receiving groove 68 in 
the locking sleeve 62 at one axial end and in a spring receiving groove 69 
in the stop flange 57 at its other axial end. Locking sleeve 62 also 
provides a ball receiving groove 66 in which the locking balls 60 reside 
when the male and female members are interconnected in the manner shown in 
FIG. 3. A second spring 70 and a releasing sleeve 72 provide a means for 
releasing the male and female members relative to one another, much the 
same way as spring 24 and sleeve 22 function in the prior art 
configuration of FIG. 1 and an O-ring 74 provides the same sealing effect 
as is provided by O-rings 26 and 46 of the prior art configurations of 
FIGS. 1 and 2 respectively. If it is desired to disconnect male member 54 
from female member 52, one merely axially slides releasing sleeve 72 from 
right to left as seen in FIG. 3, compressing spring 70 and allowing the 
locking balls 60 to separate from the ball receiving groove 66 of locking 
sleeve 62. It is then easy to readily translate the male member 54, 
including the misalignment ball 56, the locking sleeve 62 and spring 64, 
to the right as seen in FIG. 3. 
It will be observed that the inventive configuration of the present 
invention shown in FIG. 3 provides both the high pressure capability of 
the prior art configuration of FIG. 2 and the high rotation speed low 
torque capability of the prior art configuration of FIG. 1. It allows the 
locking and rotation to be controlled through the locking balls 60 while 
angular misalignment is controlled by locking sleeve 62 designed to accept 
the misalignment ball diameter. Thus, there is only low torque required 
during rotation, allowing high speed operation. The design of FIG. 3 does 
not have the point-to-point contact of the design of prior art 
configuration of FIG. 1. Instead, the locking balls rest in a groove 
larger than the locking ball diameter, that groove being in locking sleeve 
62. The approximate formula for stress at the point of contact is the 
following: 
##EQU3## 
S=Stress at point of contact, PSI. P=Load, LBs. 
E=Modulus of elasticity, PSI. 
D.sub.1 =Diameter of misalignment ball, IN. 
D.sub.2 =Diameter of locking ball, IN. 
##EQU4## 
The novel design configuration of the invention shown in FIG. 3 allows a 
larger number of locking balls to be Used. Thus in the formula above, 
D.sub.2 becomes 0.130 inches instead of 0.125 and the number of balls 
increases to 20. In this design, the ball load stress at 8000 PSIG fluid 
pressure is only 111,000 PSI. Thus, the present invention requires a very 
low torque to be applied to the misalignment ball for rotation as compared 
to the design of prior art FIG. 2. One secondary, but nevertheless 
significant advantage of the inventive configuration of FIG. 3 is its 
redundancy. More specifically, if the locking ball mechanism should fail, 
the locking sleeve 62 would still be able to accept rotation, although at 
the higher torque comparable to the prior art configuration of FIG. 2. The 
present invention provides the significant advantage of being compatible 
with requirements for both high pressure misalignment and locking 
capability, as well as high speed, low torque rotation. 
It has been shown in the present invention that stress levels are down from 
1,134,000 PSI to 111,000 PSIG over the prior art of FIG. 1 for 8,000 PSIG 
fluid pressure. To demonstrate the advantage in friction over the prior 
art of FIG. 2, the theoretical formula is: 
EQU M.sub.t =PfR.sub.f 
where 
M.sub.t =Friction torque moment, IN-LB 
P=Load, LBs. 
f=Coefficient of friction 
##EQU5## 
R.sub.0 =Outer radius of contact surface R.sub.I =Inner radius of contact 
surface 
For the prior art of FIG. 2, R.sub.0 would theoretically be the radius of 
the misalignment ball, 36. R.sub.I would be approximately R.sub.0 -- the 
equivalent diameter of the locking sleeve 40. 
For the present invention R.sub.0 would be approximately 1/2 the locking 
ball (60) diameter+the radius of the misalignment ball 56. R.sub.I is 
approximately the radius of the misalignment ball 56, -the radius of the 
locking ball 60. 
For comparison purposes, the major difference is f, the coefficient of 
friction. For a single row ball bearing configuration of the invention 
f=0.0015. The configuration of prior art in FIG. 2 resembles a cone 
clutch. The coefficient of friction for lubricated steel on steel is 0.16. 
Even for lubricated steel on sintered bronze, the coefficient of friction 
is only reduced to 0.12. 
The derived formula for the prior art of FIG. 2 is: 
EQU M.sub.t =PfR.sub.f 
Where 
M.sub.t =Friction torque moment, IN-LB 
P=Load, LBs. 
LOAD=.pi. fluid seal radius, IN.sup.2 .times.fluid pressure, PSIG 
f=Coefficient of friction 
##EQU6## 
R.sub.0 =Outer radius of contact surface=D.sub.1 /2 R.sub.I =Inner radius 
of contact surface=R.sub.0 -D.sub.2 
D.sub.1 =Diameter of misalignment ball, IN 
D.sub.2 =Diameter of locking ball, IN 
Therefore, a 1/2 inch seal holding 8,000 PSIG fluid and a 1 inch steel 
misalignment ball on a sintered bronze retainer would require 82.7 IN-LBs 
of torque. 
The formula for the present invention is basically the same except: 
EQU R.sub.0 =D.sub.1 /2+D.sub.2 /2 
Therefore, a 1/2 inch seal holding 8,000 PSIG fluid and a 1 inch steel 
misalignment ball with 0.130 inch steel locking balls would require 1.19 
IN-LBs of torque to rotate. 
It will now be understood that what has been disclosed herein, comprises a 
novel quick disconnect ball joint coupling which utilizes as a 
misalignment ball locking mechanism, a combination of a plurality of 
locking balls and a locking sleeve. The locking sleeve provides an annular 
race or groove for receiving the locking balls, thereby obviating the high 
stress point-to-point contact problem associated with prior art locking 
ball techniques, but still provides the advantage of high speed, low 
torque rotation available with the use of such locking balls. Thus the 
present invention provides the advantages of both of the prior art 
configurations of FIGS. 1 and 2 herein, but without the disadvantages of 
either. 
Those having skill in the art to which the present invention pertains, will 
now as a result of the applicant's teaching herein, perceive various 
modifications and additions which may be made to the invention. By way of 
example, the relative sizes of the misalignment ball, locking sleeve and 
locking balls may be readily altered. Furthermore, the precise mechanism 
for holding the locking sleeve in place as well as the relative positions 
of the locking ball and locking sleeve may be readily changed. In 
addition, other means for releasing the misalignment ball from its locked 
position for disconnecting the male member from the female member may also 
be provided. Accordingly, all such modifications and additions are deemed 
to be within the scope of the invention which is to be limited only by the 
claims appended hereto.