Quick coupling for pressure conduit with controlled disengagement

A quick coupling conceived for conduits under pressure comprise a latch which permits the disengagement of a male portion (10) from a female portion (1, 3) in two phases. During the first phase the male portion (10) retracts a controlled distance from its fully engaged position and arrives in an intermediary position in which the valve (5) of the female portion (1, 3) is closed. It further comprises openings (27, 28, 29) for the escape of the fluid under pressure, which openings are situated downstream from the valve (5) and this openings are opened during the said first phase of disengagement. In the final phase, the male portion (10) is completely disengaged from the female portion. The controlled disengagement in two phases is effectuated by the cooperation of a latch comprising two actually distance teeth which are positioned in a manner as to oppose each other with respect to the circumferential surface of the male portion in order to alternatively engage of disengage a projection-groove (14) of the male portion. The control disengagement in two phases avoids a shock which will otherwise be produced during uncontrolled disengagement of the two portions of a coupling in a circuit under pressure.

The present invention relates to a quick coupling comprising a male portion 
and a female portion, wherein the male portion may be inserted into the 
female portion and comprising a latch having two withholding teeth which 
are arranged on either side of the male portion in order to cooperate with 
withholding means on the male portion, thus as to produce a disengagement 
of the male portion from the female portion in two phases corresponding to 
one single pressing and releasing of said latch, whereby said female 
portion comprises a closing valve which is urged towards its closed 
position when said male and female portions are disengaged and which is 
open as a result of the insertion of the male portion into the female 
portion. 
A quick coupling as described hereinabove is described in French patent 2 
514 855, wherein the latch comprises three withholding teeth, whereof two 
are arranged axially separated within the interior of an axial boring of 
the latch, such as to define a certain axial distance along which the male 
portion may move, whereby two teeth are arranged on the same side of the 
radial boring of the latch relative to the male piece which is inserted 
into said axial boring of the latch, and a third tooth is arrange in an 
axial position between two first teeth and on the oposite side of the 
radial boring of the latch. 
Thus, a shoulder which is formed at the outer surface of the male portion 
is latched in its completely coupled position by a first one of the two 
first teeth, and an initial pressing of the latch releases this first 
tooth from the shoulder of the male portion at the same time as the third 
tooth enters into the axial passage of the shoulder of the male portion 
during the retracting movement of the male portion, whereby the later 
retracts along an axial distance corresponding to the axial distance 
between the first and the third tooth. 
Thereafter, the latch is released in order to return into its initial 
position, urged by a spring, and the third tooth will thereby be 
disengaged from the shoulder of the male piece and at the same time the 
second of the first two teeth will engage into the axial passage of the 
shoulder of the male piece in order to permit that the male piece may 
retract again along an axial distance corresponding to the difference 
between the axial positions between the third and the second tooth which 
retains the male piece in a third axial position before said male piece 
may finally be released by a second pressing of the latch which retracts 
said second tooth from the shoulder of the male piece, thus permitting 
complete extraction of the male piece whereafter the latch is again 
released and returns in its initial position. 
Thus, the male piece is disengaged from its connection with the female 
portion by a sequence of two pressing operations on the latch, the first 
pressing permitting a partial disengagement during which the portion of 
the fluid under pressure which is located downstream of the valve may 
escape from the coupling before a complete disengagement of male and 
female portions, which has the advantage to avoid a shock occasioned by 
the residual pressure in the coupling during disengagement or even before 
the complete closure of the valve. 
However, that the complete disengagement necessitates a double action of 
the latch which produces the progressive disengagement of the male 
portion, and it is therefore one of the objectives of the present 
invention to create a quick coupling comprising a latch which permits 
controlled disengagement of male and female portions during a single 
pressing and releasing of the latch, whereby the advantages of the escape 
of the residual pressure before complete liberation of the male piece are 
maintained. 
French patent application 2 511 115 describes a coupling comprising two 
independent axially separated latches which necessitate also a double 
action for release. 
French patent application 1 503 989 describes a system having a single 
latch which produces a retraction of the male piece in two phases during a 
single action of the latch. 
However, the engagement of the male piece within the seal of the female 
portion is such, that the male portion is not disengaged from this seal or 
from the axial guiding portion respectively, when it is located in its 
intermediary position, so that the residual pressure is not rapidly 
released after a first partial retraction of the male piece. 
It is therefore another object of the present invention to provide a quick 
coupling wherein the release of residual pressure may take place in 
sufficiently rapid manner in order to avoid accidental early release of 
the male portion from its intermediary position. 
This object is obtained by a quick coupling as described hereinabove which 
is further charaterized in that the closing valve comprises a hollow 
cylindrical portion which receives the front portion of the male portion 
and which comprises a seal for sealing the connection between the valve 
and the male portion, said cylindrical portion comprising a plurality of 
radial openings downstream from said seal and in that said first two teeth 
are separated one from the other by an axial distance sufficient in order 
to permit a retraction of the male portion relative to the female portion 
during a single pressing of the latch in order to close the valve and 
disengage said openings in order to permit the escape of the residual 
pressure fluid downstream of the valve, while maintaining the male portion 
within the female portion, whereas subsequent release of the latch results 
in a complete disengagement of the male portion from the latch. 
According to a preferred embodiment of the invention the coupling may 
comprise a male portion and a female portion within which the male portion 
may be inserted during the coupling operation, said female portion 
comprises a closing valve which is urged towards its closed position when 
the male and female portions are disengaged and which is opened by the 
movement of the male portion during its insertion into the female portion, 
said female portion comprises a latch capable of being moved in a 
direction perpendicular to the longitudinal axis of the female portion 
between a rest position and a working position, whereby said latch 
comprises whithholding teeth which engage with a circumferential groove or 
projection of the male portion, so that the movement of the latch may 
block the groove or the projection against an axial movement in the sense 
of a complete liberation thereof, whereby the male portion comprises a 
circumferential shoulder between a circumferential projection and 
circumferential groove, one of said teeth being disengaged from the axial 
trajectory of the shoulder and the second tooth being located within the 
axial trajectory of the shoulder when the latch is in its rest position, 
whereas the first tooth is located within the axial trajectory of the 
shoulder and the second tooth is disengaged from said axial trajectory 
when the latch is located in its working position, whereby said latch 
comprises two withholding teeth which are located axially separated one 
from the other by a distance sufficient to permit partial withdrawal of 
the male portion relative to the female portion during a single pressing 
of the latch in order to simultaneously close the valve and disengage the 
male portion from the valve so as to permit the escape of residual 
pressure of the fluid downstream of the closed valve, while maintaining 
the male piece within the female piece, whereby the release of the latch 
produces complete disengagement of the male portion resulting from the 
withdrawal of the first tooth. 
According to a different embodiment of the invention, the female portion 
may comprise a second seal provided to seal the interior of the female 
portion from the exterior when the valve is in its open position and 
further to act as a sealing means for the valve itself when said valve is 
its closed position. 
According to a particularly preferred embodiment of the present invention, 
the valve may comprise a hollow cylinder having a closed front portion and 
a cylindrical portion provided with holes which may be closed by said 
second seal when the valve is in its closed position, whereby said 
cylindrical portion comprises two sections of different diameter of an 
axial hole, which form between them a shoulder and a circumferential 
groove which is provided for said second seal, whereby the portion of 
larger diameter receives the front part of the male portion. 
In this embodiment, the female portion may comprise a spring solliciting 
the valve into its closed position. 
The front portion of the valve may comprise a frustro-conical surface which 
is designed in order to match a corresponding frustro-conical surface of 
the first seal when the valve is closed. 
In this same embodiment of a coupling according to the present invention, 
the section of larger diameter of the cylindrical portion of the valve may 
comprise several radial borings downstream from the first seal which 
permit, when the valve is closed and when the male portion has just be 
disengaged from said section of larger diameter of the cylindrical portion 
of the valve, to let the residual fluid under pressure, present within the 
cylindrical portion of the valve escape to the exterior. 
Advantageously, the female portion of the coupling according to the present 
invention may comprise at a position downstream of the valve, a radial 
boring receiving the latch, said latch comprising a cylinder including an 
axial hole for the passage of the male portion. 
According to another preferred embodiment of the invention the radial hole 
of the latch may comprise projections pointing towards the interior of the 
hole and thus forming said withholding teeth. 
Advantageously the radial boring of the female portion is open on one side 
of the female portion and this opening is sufficiently large for the 
passing of the latch, and at the opposite side of this radial boring of 
the female portion there is a smaller opening which communicates with the 
radial openings of the portion of larger diameter of the cylindrical part 
of the valve in order to permit the residual fluid to escape from the 
interior of the valve to the exterior of the female portion before 
complete disengagement of the male and female portions.

The invention will now be described in more detail with reference to the 
drawings which illustrate examples of the invention. 
FIG. 1 illustrates a quick coupling according to the invention in a 
completely coupled position, 
FIG. 2 illustrates the same coupling in a partially disengaged position, 
permitting escape of the fluid under pressure, while maintaining the male 
portion within a retracted position after having pressed the latch, and 
FIG. 3 illustrates the coupling of FIG. 2 once the fluid under pressure has 
escaped and once the latch has returned to its initial position, 
FIG. 4a-4f illustrates the same coupling in a series of six phases 
beginning with a position immediately before the introduction of the male 
portion into the female portion until the position of disengagement 
corresponding to FIG. 3. 
With reference to FIG. 1, a coupling according to the present invention is 
illustrated in its completely coupled position, whereby the left side of 
the drawing represents the upstream side corresponding to a source of 
pressurised fluid, and the right side of the drawing represents the 
downstream side in direction of which the fluid under pressure flows after 
complete connection of the coupling. 
The female portion comprises a first cylinder 3, called outer cylinder, 
which comprises at its upstream side an interior threading, and a second 
cylinder 1 comprising at its downstream side an outer threading which is 
screwed into the interior threading of the outer cylinder, thus forming a 
housing for a first seal 4 which projects towards the interior of the two 
cylinders. 
The interior cylinder 1 comprises a shoulder 15 forming a seat for a spring 
2. 
At the interior of the outer cylinder and also partially at the interior of 
the inner cylinder there is a valve 5 comprising a front part 16 as well 
as a hollow cylindrical portion 17 which is closed at its upstream side by 
said front part 16, said valve 5 being arranged in axially sliding manner 
within the interior of the axial open space of the outer cylinder, whereof 
the inner diameter is essentially equal to the outer diameter of the 
cylindrical portion 17 of valve 5 in order to permit exact guiding of 
valve 5 during its axial movement within the outer cylinder 3 during the 
different phases of coupling and disengaging of the male and female 
portions. 
The cylindrical portion 17 comprises at its upstream end radial openings 18 
and the front part 16 on one side and the cylindrical portion on the other 
side of these openings comprise a frustro-conical surface 19 as well as an 
annular surface formed by a polygonal generatrix 20 respectively designed 
to match identical surfaces of the seal 4 when the valve is in its closed 
or open position respectively. 
FIG. 1 illustrates the open position of valve 5 where the "polygonal" 
surface is in contact with the seal 4 so that the openings 18 are open and 
permit the passage of fluid, under pressure or not, from the upstream side 
of the female portion into the interior of the valve, passing through the 
openings 18. 
FIGS. 2 and 3 illustrate positions of the coupling in which the valve is 
closed, whereby the frustro-conical surface 19 of the front part 16 abuts 
on the frustro-conical surface of the sealing 4 in order to hermetically 
close the part of the female portion which is located upstream of the 
valve. 
The cylindrical portion 17 of valve 5 comprises an inner boring having two 
sections of different diameter whereby the intersection between these two 
sections forms a shoulder adjacent to a circumferential groove in which a 
sealing 6 is housed, which is provided to sealingly close the interior of 
valve 5 and the interior of male portion 10 against the boring of the 
outer cylinder when the male portion 10 is completely connected within the 
female portion. 
The outer cylinder 3 comprises a radial boring 21 having a diameter larger 
than the diameter of its axial boring, and said radial boring houses a 
latch of cylindrical shape which comprises a radial boring 22 which is 
positioned more or less coaxial with the axial boring of the outer 
cylinder 3 in order to permit the passage of male portion 10 through 
radial boring 22 of the latch. 
The male portion 10 comprises an insertion end 24 having an exterior 
diameter essentially equal to the interior diameter of the section of 
larger diameter of cylindrical portion 17 of claim 5 whereby the insertion 
end 24 of the male portion 10 may be introduced into the cylindrical 
portion 17 of the valve until it abuts against seal 6. 
Somewhat downstream of the insertion end 24 of the male portion 10, the 
later comprises a circumferential projection 14 accompanied by a 
frustro-conical portion 23 forming a ramp, the largest diameter of which 
corresponding to the outer diameter of the projection 14, and said 
projection 14 is followed, downstream, by a large groove 8 which extends 
until the wider portion 25 of the male portion 10 whereby a ramp of 
frustro-conical shape is formed between projection 8 and portion 25. 
The radial boring 22 of latch 7 comprises a first tooth 12 situated on the 
accessible side of latch 7, and a second tooth 11 is positioned opposite 
of the first tooth 12 close to the inner end 7a of latch 7. 
A spring 9 pushes against shoulder 26 of the radial boring 21 of the 
exterior cylinder 3 in order to solicit latch 7 into its rest position 
such as illustrated in FIG. 1. 
In this rest position, tooth 12 is located so that it is at a radial 
distance from axis A of the coupling in order to stay outside of the axial 
trajectory of the projection 14 of the male portion 10. 
In this rest position of latch 7, as indicated in FIG. 1, the second tooth 
11 is located within the trajectory of the circumferential groove 14 and 
of the ramp 23 of the male portion 10 in order to permit locking of the 
male portion 10 in its completely coupled position as illustrated in FIG. 
1, whereby the second tooth 11 either abuts against shoulder 14a of 
projection 14, or as indicated in FIG. 3 permitting, the introduction of 
the male portion into the female portion whereas ramp 23 slides over tooth 
11, so as to drive latch 7 into its working position, until tooth 11 
snapps behind circumferencial groove 14 as soon as the coupling is 
completed such as indicated in FIG. 1. 
The section of larger diameter of cylindrical portion 17 of the valve 5 
comprises, downstream of the second seal 6, radial openings 27 which 
permit, in the closed position of valve 5 as indicated in FIGS. 2 and 3, 
communication between the interior of the cylindrical portion 17 and the 
radial boring 21 of latch 7, said radial boring 21 comprising further an 
opening 28 near the shoulder 26 which plays the role of a seat for spring 
9, so that a residual volum of pressurized fluid comprised within the 
cylindrical portion 17 of valve 5 and within the male portion 10 as well 
as in all downstream conduits may escape to the exterior during an 
operational phase of the coupling as illustrated in FIG. 2. 
In order to disengage the male and the female portions, one simply presses 
manually or mechanically against the accessible end of latch 7, so that 
tooth 11 which is situated close to the interior end of latch 7 be 
disengaged of groove 14, whereas at the same time tooth 12 enters into the 
space constituting the trajectory of projection 14, however, this tooth 12 
is located a certain axial distance downstream of tooth 11. 
This pressing down of latch 7 permits thus a certain withdrawal of the male 
portion as a result of the pressure of the fluid or simply by manual 
traction in the case where the fluid is not under pressure until an axial 
position in which the shoulder 14a of projection 14 abuts against the 
shoulder 12a of tooth 12, in which position the male portion 10 is 
maintained as long as latch 7 is pressed down. 
During this withdrawal, the end position of which is represented in FIG. 2, 
the valve is pushed into its closed position by spring 2 and by the 
pressure of the upstream fluid, and end 24 of the male portion 10 will be 
disengaged simultaneously from sealing 6 and, at least partially from 
radial openings 27 of the cylindrical portion 17 of the valve in order to 
permit the pressurized fluid present upstream of the valve to escape by 
openings 27, the radial boring 21 of latch 7 and finally throug opening 28 
in order to eliminate any force which may be occasioned by the pressurized 
fluid downstream from valve 5, and thus permitting a complete 
disengagement of the male portion after withdrawal of tooth 12 into its 
initial position, corresponding to the rest portion of latch 7 which is 
illustrated in FIGS. 1 and 3, without danger of a shock which may normally 
be encountered during disengagement of male and female portions without 
restrictions, while the conduits downstream from valve 5 are still under 
pressure. A boring 29, parallel to axis A is provided in order to create a 
second escape trajectory for the pressurized fluid in case that opening 28 
would accidentally be blocked by the hand of the operator. 
In the position as indicated in FIG. 3, the interior of the conduits 
downstream of valve 5 is without pressure and the male portion 10 may be 
manually retracted, or be returned into its position of complete coupling 
by simply pushing the male portion so that tooth 11 slides along ramp 23 
until it snapps behind shoulder 14a of circumferential projection 14 of 
the male piece. 
FIG. 4 ilustrates subsequent phases of coupling and disengagement of the 
coupling illustrated in FIGS. 1 to 3, whereby position a) illustrates the 
phase immediately before complete connection, in which phase the valve is 
still closed and the latch is in its rest position. 
In phase b) the male portion is almost entirely introduced into the female 
portion, the valve is open, hermetical sealing between the male portion 
and the valve is established by the appropriate seal and the tooth is in a 
position immediately before snapping behind the circumferential projection 
of the male piece. 
In position c), the valve is open and the male portion is blocked in its 
position of complete connection by the second tooth which has just snapped 
behind the circumferential groove. 
In phase d), the latch is illustrated in its pressed-down position so as to 
withdraw the second tooth from the trajectory of the circumferential 
projection and, as soon as this withdrawal is completed, the valve is 
closed under the action of its spring, while the male portion retracts 
until the circumferential projection abuts onto the first tooth of the 
latch which is situated at the side of the accessible end of the latch. 
This position is illustrated in phase e). 
In this position the pressurized fluid which is contained in the conduits 
downstream from the valve may escape whereas the male portion assumes an 
idle position. 
Thereafter, in phase f), the latch is released so that the second tooth 
abuts onto the insertion end of the male portion upstream from the 
circumferential projection and the male portion may now be completely 
withdrawn from the female portion. 
The valve stays of course in its closed position during phases e) and f). 
The invention has been described hereinabove with reference to a possible 
embodiment, it being understood that numerous modifications may be made by 
the man of the art without departing from the spirit of the invention. 
The principle of the present invention resides in the fact to provide a 
complete disconnection of a coupling in a single pressing operation onto 
the latch and its subsequent release, so that the pressing-down of said 
latch permits a partial release between the male and female portions of 
the coupling, whereby the following release of the latch permits to 
completely disengage the two portions. The first phase of partial release 
produces an intermediary positioning of the male portion within the female 
portion during which the pressure of any fluid downstream of the valve of 
the female portion may quickly and securely be released before engaging 
into the second phase of the complete disengagement. 
In order to permit this escape of the pressurized fluid downstream of the 
valve of the female portion, it is necessary to provide a retraction 
movement for the male portion which is triggered by pressing-down of the 
latch only, whereby this retraction movement is effectuated between its 
fully coupled and its partially disengaged position, and which permits 
simultaneously to close the valve and to open the conduits for the escape 
of the fluid.