Valve coupler with decompression

This coupler with valves is of the type which includes an outer tubular body (2), equipped, at one end (2") with means (3) of rigid connection with a source of fluid under pressure, at the other end of which is made the female fitting (7') of the coupler, this female fitting (7'), which contains the valve (14), situated on the feed circuit side, being arranged to permit the engagement and the locking, in its bore, of the male fitting (11) of this coupler, which, in turn, contains the valve (13), situated on the side of use of the fluid under pressure. The head of the valve (14), situated on the feed side, has a bore (14a), supporting an auxiliary valve (22), of which the return spring (25) is weaker than that (15) of the main valve (14), and which can be pushed back into open position by the valve (13) of the male fitting (11), as soon as this latter exerts a push against it, this auxiliary valve (22) being arranged so that its opening puts into communication the spaces (28, 31) situated on either side of the seat (18) of the main valve (14).

BACKGROUND OF THE INVENTION 
This invention relates to a valve coupler with decompression. 
Thus, the invention relates to a valve coupler of the type which includes 
an outer tubular body, equipped at one end with rigid connection means to 
a source of fluid under pressure, to the other end of which is brought the 
female fitting of the coupler, and this female fitting, which contains the 
valve situated on the feed circuit side, being designed to permit the 
engagement and locking, in its bore, of the male fitting of this coupler 
which, in turn, contains the valve situated on the user side of the fluid 
under pressure. 
In the connection of the male fitting into the female fitting of such a 
coupler, it is necessary to prevent the valve situated on the user side, 
that is, in the male fitting, from opening before that situated on the 
feed side, namely, in the female fitting. This purpose is usually attained 
because, generally, there prevails in the user circuit, a residual 
pressure which assists the return spring of the valve of the male fitting, 
to maintain it in a closed position. However, this advantage is cancelled 
if there prevails, in the feed circuit, a residual pressure greater than 
that of the user circuit, since, in this case, the valve of the user 
circuit will be opened before that of the feed circuit. 
There is known from French patent application No. 69 41086 (Pat. No. 
2,024,539), a coupler of this type in which, with the valve of the female 
element situated on the feed side, is associated an auxiliary valve 
designed to be opened before the main valves, situated on the feed side 
and the user side, respectively. This device, by causing a fall of the 
residual pressure possibly prevailing in the feed circuit, has for its 
purpose the assuring of the opening of the main valve situated on the feed 
side before that of the main valve situated on the user side. 
To obtain the opening of the auxiliary valve before that of the main valves 
in the coupler according to this French Patent, the return spring, in the 
closing position of the auxiliary valve, is chosen stronger than those of 
the main valves, which are both supposed to be assisted by the high 
residual pressure which ma prevail upstream of each of them. 
The return spring of the auxiliary valve, which is necessarily stronger 
than those of the main valves, and which must be lodged inside a bore of 
the main valve situated on the feed side, imposes on this latter a great 
dimension, and thus, considerably increases the cost of manufacture of 
this coupler. 
Moreover, to engage the male fitting, bearing the main valve, situated on 
the user side, in the female fitting, if a high residual pressure prevails 
on the feed side, it is necessary to overcome the force of the return 
spring, which does not facilitate this engagement. 
SUMMARY OF THE INVENTION 
The present invention is intended to remedy this difficulty, starting with 
the principle that a very low feed rate will suffice to cause the residual 
pressure in the feed circuit to fail. For this purpose, in the coupler 
concerned, and which is of the type mentioned, the return spring of the 
auxiliary valve is weaker than that of the main valve, situated on the 
feed side, with which it is associated, so as to permit it to be pushed 
into the opening position by the valve of the male fitting, situated on 
the user side, as soon as this latter pushes against it, and consequently, 
before the opening of the main valve of the female fitting with which it 
is associated. Thus, the opening of the auxiliary valve is obtained before 
that of the two other valves of the coupler, whatever the values of the 
other residual pressures which may prevail, upstream of one and/or the 
other of the main valves. 
It should be noted also that the return spring of the auxiliary valve has 
only for its purpose the return of this latter into the closed position, 
so that its force may be chosen at a very low value. It might also be 
omitted in case the coupler is used vertically, with the female fitting 
situated above the male fitting, gravity then playing the part of the 
return spring into the closed position of the auxiliary valve. 
The locking of the male fitting into the female fitting may be obtained by 
screwing the first into the second. This advantageous arrangement might 
also be applied to couplers of the type mentioned, in which the locking of 
the male fitting into the female fitting is obtained with the aid of 
locking balls; that is, couplers of the type mentioned in which the outer 
tubular body lodges a tubular element, movable axially in both directions, 
and of which the front end, corresponding to the free end of the tubular 
body, which forms the female fitting of the coupler, bears, in an annular 
row of perforations, serving them as lodgings, locking balls, designed to 
be engaged and held in an outer annular hollow provided, for this purpose, 
near the end of the associated male fitting of the coupler, a return 
spring tending to bring this tubular element back into an intermediate 
stable position, in which the annular row of perforations, lodging the 
locking balls, coincides axially with an internal radial rib with conical 
sides, of the tubular body, to hold the balls in locking position; that 
is, in projecting radially to the inside of the bore of the mobile tubular 
element, and this latter bearing, on the side of its rear end, a valve 
normally held shut by a spring, and designed to be moved back into open 
position by the valve of the male fitting when this latter is engaged in 
the female fitting. 
There is known through the French patent application No. 85 07821 of the 
applicant, a coupler of this type, in which the course of opening of the 
valve of the feed circuit is temporarily augmented to permit a locking of 
the male fitting into the female fitting, before the opening of the valve 
of the user circuit, this opening being commanded by the pressure of the 
feed fluid, with the opening of the feed circuit. 
Naturally, the present invention may also be applied to this type of 
couplers. In this case, the head of the main valve of the feed circuit has 
a bore coaxial with its tubular stem and serving as a guide for the stem 
of the auxiliary valve, and of which the diameter, less than that of the 
bore of the stem of the main valve, creates a shoulder, forming the seat 
of the auxiliary valve, of which the head is lodged in the bore of the 
stem of the main valve, the length of the stem of the auxiliary valve 
being greater than the length of the bore of the head of the main valve, 
and radial openings made in the wall of the head and of the stem of the 
main valve, causing the bore of the head and that of the stem, 
respectively, to communicate with the spaces of the bore of the mobile 
tubular element, situated before and after the seat of the main valve. 
In any case, the invention will be well understood with the aid of the 
description which follows, with reference to the attached schematic 
drawing, showing, by way of example, and without intent to limit, one form 
of execution of this coupler which, in this example, is of the type with 
locking by balls.

DETAILED DESCRIPTION OF THE INVENTION 
As the drawing shows, the coupler of the invention is a coupler with valves 
of a known type, including an outer tubular body (2), provided, at its 
rear end (2"), with a threaded fitting (3), equipped with a thoric joint 
(4), permitting its hermetic connection with a source of fluid under 
pressure, not shown in the drawing. 
In the example illustrated in the drawing, for reasons of mounting 
possibilities, the tubular body (2) is actually composed of two coaxial 
elements, one in front (2a), the other at the rear (2b), assembled end to 
end with a threaded inner ring (5). 
Near its front end (2'), the tubular body (2) has an inner radial rib (6) 
with conical sides, one inner (6a) and the other outer (6b), of which the 
function will be explained later. 
Inside the body (2) is mounted, axially mobile in both directions, an inner 
tubular element (7), of which the front end (7') corresponding to the 
front end (2') of the body (2), forms the female fitting of the coupler 
and bears, in an annular row of perforations (8), serving them as 
lodgings, locking balls (9), normally held in radial projection to the 
inside of the bore of the front end (7') of the tubular element (7) by the 
rib (6) of the body (2), the diameter of the balls (9) being greater than 
the thickness of the wall of the tubular element (7) in the zone of the 
annular row of perforations (8). It should be noted that each perforation 
(8) has, at its radially inward end a restriction, opposing the free 
passage of the balls (9). These balls are designed to lock, in a manner 
known per se, the male fitting (11) of this coupler, shown in FIGS. 2 and 
3, by engagement in a peripheral hollow (12) provided near the free end of 
the male fitting (11). 
With each of the fittings, male (11) and female (7') of this coupler is 
associated a valve, (13) and (14) respectively, normally held in closed 
position by a return spring. In the drawing, only the return spring (15) 
of the valve (14) associated with the female fitting (7') is shown. Each 
of these valves, (13) and (14), is designed to rest against the other 
during the engagement of the male fitting (11) in the female fitting (7'), 
so as to cause its opening and its holding in open position so long as the 
male fitting (11) remains locked in the female fitting (7'). 
A spring (16), surrounding the mobile tubular element (7), and 
consequently, lodged in an annular space (17), separating the tubular 
element (7) from the body (2), tends to hold this latter in an 
intermediate stable position, illustrated in FIGS. 1 to 3, in which 
position the annular rows of perforations (8) coincide axially with the 
rib (6), and consequently, in which the balls (9) are held by the rib (6) 
in the radially interior locking position. 
For this purpose, the spring (16) rests against two pairs of shoulders, 
equidistant one from the other, one of these pairs being made on the outer 
cylindrical surface of the mobile tubular element (7), while the other 
pair is made on the inner cylindrical surface of the tubular body (2). 
As the drawing, and especially FIG. 1 shows, the head of the valve (14), 
hereinafter called the main valve, of which the seat (18) is made in the 
bore of the tubular element (7), and of which the tubular stem (19) lodges 
its return spring (15), has itself a bore (14a), coaxial with the stem 
(19) and in which is mounted, sliding, an auxiliary valve (22). The bore 
(14a) of the head of the main valve (14) has a diameter less than that of 
its stem (19), so that a shoulder (24) results, designed to serve as seat 
for the head (22a) of the auxiliary valve (22). The return spring (25) 
tends, normally, to hold the head (22a) of the auxiliary valve (22) 
resting against its seat (24). In this closed position, the stem of the 
auxiliary valve (22) has a length which permits it to project beyond the 
free end of the bore (14a) of the head of the valve (14), so as to be 
actuated, in the open position, by the valve (14) of the male fitting (11) 
with the introduction of this latter into the female fitting (7'), before 
any axial movement of the main valve (14) and of the tubular element (7). 
For this purpose, the return spring (25) of the auxiliary valve (22) is 
less strong than the return spring (15) of the main valve (14), than the 
return spring (16) of the tubular element (7) and than the return spring, 
not shown in the drawing, of the valve (13) of the male fitting (11). 
In the example shown in the drawing, the rear end of the stem (19) of the 
main valve (14) is mounted to slide in a sleeve (21), itself mounted to 
slide in a guide ring (20), borne by the mobile tubular element (7). The 
return spring (15) of the main valve (14) is compressed between the bottom 
(21a) of the said sleeve (21) and an inner radial rib (23), formed in the 
bore of the stem (19) by a circlips. The front surface of this rib (23) 
serves as rear resting point for the return spring (25) of the auxiliary 
valve (22). 
It should be noted that the wall of the bore (14a) of the head of the main 
valve (14) has a radial opening (27) or a row of openings, putting this 
bore (14a) in communication with the space (28) of the bore of the tubular 
element (7), situated before the main valve (14). On its side, in turn, 
the wall of the bore of the stem (19) of the main valve (14), has a radial 
opening (29), or several radial openings, putting this bore in 
communication with the space (31) of the bore of the mobile tubular 
element (7) situated behind the main valve (14). 
At rest, as shown in FIG. 1, the main valve (14) and the auxiliary valve 
(22) are in closed position, and no communication is possible between the 
spaces (28) and (31). As soon as, after introduction of the male fitting 
(11) into the female fitting (7'), the valve (13) of the male fitting 
comes in contact with the stem of the auxiliary valve (22), this latter is 
moved into open position, in the direction of the arrow (26), but without 
causing the opening of the main valve (14), because of the weakness of the 
return spring (25) in relation to that of the spring (15). Thus, because 
of this weakness of the spring (25) in relation to the return spring of 
the valve (13), this latter can act while remaining in closed position. 
In this position, shown in FIG. 2, we see that the fluid can circulate 
freely between the spaces (28) and (31). As a result, therefore, if, 
during the connection of this coupler, there prevails, in the feed 
circuit, that is, between the connection (3) and the space (31), a greater 
pressure than that prevailing in the user circuit, it is possible, without 
any harmful result to the operation of this coupler, to cause the pressure 
of the feed circuit to fall instantly before finishing the connection of 
the coupler. Namely, as soon as the auxiliary valve (22) opens, as shown 
in FIG. 2, the fluid under pressure, contained in the space (31), as well 
as in the part upstream of the feed circuit, being able to flow into the 
space (28), situated in the female fitting (7'), this pressure of the feed 
circuit falls instantly, since at this moment, the source of pressure is 
still insulated from the feed circuit. 
The engagement of the male fitting (11) into the female fitting (7'), 
without opening of the valve (13) of the male fitting (11), can then be 
normally continued until its locking, with the aid of the balls (9); it 
suffices for this that the retreat course of the main valve (14) permits 
it. 
In the example shown in the drawing, this retreat course is made possible, 
at least during the connection of the coupler, by a device according to 
that described in French patent application No. 85 07821, filed in 1985, 
of the applicant. 
After locking of the male fitting (11) into the female fitting (7') and 
opening of the feed circuit, the elements of the coupler (2) occupy their 
normal operation position, as shown in FIG. 3, in which position the three 
valves, namely, the valve (13) of the male fitting (11), the main valve 
(14) of the female fitting (7') and the auxiliary valve (22), are in open 
position. 
It is easy to see that, with the retraction of the male fitting (11) out of 
the female fitting (7'), by simple traction directed outward, that is, in 
the direction opposite that illustrated by the arrow (26), all the 
elements lodged in the body (2) of this coupler will resume their normal 
rest position, as shown in FIG. 1.