WO2014097001A1

WO2014097001A1 - Quick coupling for hydrodynamic systems

Info

Publication number: WO2014097001A1
Application number: PCT/IB2013/059792
Authority: WO
Inventors: Salvatore Orlando
Original assignee: Tec-Ind Di Salvatore Orlando
Priority date: 2012-12-18
Filing date: 2013-10-30
Publication date: 2014-06-26
Also published as: ITMI20122164A1

Abstract

A quick coupling for hydrodynamic systems comprises a female element having an outer body (3) and an inner body (4), associated in a sealed manner with the outer body (3) by a plurality of seals (5a, 5b, 5c) in hydrodynamic equilibrium with each other; the inner body (4) is relatively translatable with respect to said outer body (3); an axial channel (8) formed inside the inner body (4) and extending for the entire length of the female element (2); a valve (9), positioned inside the axial channel (8), comprising a shutter (10) supported by a respective valve-guiding slider (11 ) that is slidable inside the axial channel (8). At least a first seal (5a) of the seals (5a, 5b, 5c) in hydrodynamic equilibrium is located at the intrados of the inner body (4).

Description

QUICK COUPLING FOR HYDRODYNAMIC SYSTEMS

The object of the present invention is a quick coupling for hydrodynamic systems, particularly for hydraulic systems.

This invention can be used for all quick hydraulic couplings that utilise incompressible working fluids.

Quick couplings currently known on the market have a female element connected to a distributor or to a hydraulic circuit and that can be coupled to a male element, which is pushed into the female element, whereas mutual disengagement takes place by tugging on the male element .

Various types of quick couplings exist, the types being based on the operating pressure conditions of the two elements: male and female element not under pressure, male under pressure and female discharged, or male and female under pressure.

In the case of the female element being under pressure, even only in the presence of possible residual pressure inside the female element, insertion of the male element proves to be particularly difficult or even impossible, until the pressure in the female element has been adequately reduced.

For this purpose, inside the female element, valves can be provided so as make it possible to discharge the portion of the internal working fluid creating the excess pressure that prevents engagement of the male element, said fluid being discharged outside the female element.

Specifically, these valves can be provided inside the female element in various positions in which interference takes place between the valve and an inner body of the female element or another part that is movable in relation thereto.

There are, however, types of couplings that do not have this drawback, that is, they do not operate with the female element under pressure, and discharge valves are therefore not provided or needed for couplings of this type.

Couplings with a valve have an internal structure that differs from that of couplings without a valve.

Manufacturers and suppliers of these couplings are thus faced with the need to have numerous components available in stock that differ according to the type of coupling needed by the user, with resulting inconveniences relating to the space occupied, design costs, the industrialisation, production and logistics management costs of the numerous components needed to meet the demand based on different types of couplings.

The aim of this invention is therefore to realise a quick coupling for hydrodynamic systems that overcomes the reported drawback of the prior art.

Specifically, the aim of the present invention is to propose a quick coupling for hydrodynamic systems that makes it possible to reduce the number of components required for the realisation of couplings of different types, and that enables simpler and more economical management of the inventory in stock.

A further aim of the present invention is to offer a quick coupling that has mechanical components that are flexible and versatile, so as to be adaptable to the current needs of each individual user.

The defined technical task and the specified aims are substantially achieved by a quick coupling for hydraulic systems, comprising the technical characteristics stated in one or more of the claims below.

Further characteristics and advantages of the present invention will become more apparent from the approximate, and thus non-limiting, description of preferred, but not exclusive embodiments of a quick coupling for hydrodynamic systems, as illustrated in the accompanying drawings, in which:

- Figure 1 is a partially sectioned side view of a quick coupling for hydrodynamic systems in accordance with the present invention, in a first embodiment;

- Figure 2 is a partially sectioned side view of a quick coupling for hydrodynamic systems in accordance with the present invention, in a second embodiment.

A quick coupling for hydrodynamic systems, preferably hydraulic systems, is generically indicated by the reference numeral 1 . In general, this coupling is suitable for use with incompressible fluids.

This coupling comprises a female element 2 having a substantially longitudinal extension along an axis 2a and comprising an outer body 3 and an inner body 4, both of which are relatively translatable with respect to each other, in an axial direction.

The inner body 4 is associated in a sealed manner with the outer body 3 by a plurality of seals, advantageously in hydrodynamic equilibrium with each other.

In other words, along the axis 2a, the sum of the thrust forces generated on these seals by the working fluid under pressure contained inside the female element 2 is substantially equal to zero.

The seals preferably comprise O-rings and anti-extrusion rings.

The outer body 3 is substantially made up of three portions rigidly connected to each other. In particular, there is a head portion 3a, located at a first end 2' of the female element 2, at the socket section for a male element 6 that can be coupled with the female element 2.

There is also an end portion 3b, located at a second end 2" of the female element 2 and rigidly connectable to a distributor or to a hydraulic circuit. A middle portion 3c is located between the head portion 3a and the terminal portion 3b.

The three portions 3a, 3b and 3c of the outer body 3 are connected to each other by means of specific threads 40.

The inner body 4 instead comprises a front portion 4a at the first end 2' of the female element 2 and it delimits the seat 7 for insertion of the male element 6.

A rear portion 4b is fastened to this front portion 4a by means of the thread

41 and it extends almost for the entire female element 2, leaving a certain margin for movement towards the terminal portion 3b, so as to enable sliding of the inner body 4 with respect to the outer body 3.

The inner body 4 has an axial channel 8 that extends for the entire length of the female element 2.

A valve 9 is inserted inside this axial channel 8 and it comprises a shutter 10 that is slidably supported by a respective valve-guiding slider 1 1 , which is, in turn, slidable inside this axial channel 8.

The shutter 10 performs its task by abutting against an annular shoulder 12, which is realised by an internal protrusion of the front portion 4a of the inner body 4. In a resting or closed position of the valve 9, the shutter 10 is kept against this annular shoulder 12 by the cooperation of two helical thrust springs: a first spring 13 interposed between the shutter 10 and the slider 1 1 , and a second spring 14, preferably more rigid than the first spring, located behind the slider 1 1 , between a rear part of the slider 1 1 and an abutment element 15.

The abutment element 15 is rigidly connected to the outer body 3, preferably to the terminal portion 3b by means of a thread 42 located inside the terminal portion 3b.

Two additional elastic elements, specifically two additional helical contrast springs, are interposed between the outer body 3 and the inner body 4. In particular, there is a first spring 16 that coordinates the relative translational movement between the inner body 4 and the outer body 3, and the subsequent return to the rest position. This first contrast spring 16 is located between the head portion 3a of the outer body 3 and the front portion 4a of the inner body 4, said portions 3a, 4a forming two opposite concentric pairs of shoulders 17, 18 that face each other, and against which the spring abuts.

Advantageously, at least one ring nut 19 can be provided, located in front of the first spring 16, where the front part of the spring 16 is the part facing the first end 2' of the female element 2, against which the spring abuts so as to resist the shoulders 17. A second contrast spring 20 is located in a chamber 21 delimited by the middle portion 3c of the outer body 3 and by the rear portion 4b of the inner body 4.

As can be seen in Figures 1 and 2, inside this chamber 21 , there is also an external slider 22, against which the rear part of the second spring 20 abuts. The external slider 22 is limited in its travel by a shoulder 23, which is blocked, in turn, by a recess in the terminal portion 3b of the outer body 3. The second contrast spring 20 governs the movement of the external slider 22 with respect to the inner body 4.

The external slider 22 cooperates with the inner body 4 and the valve- guiding slider 1 1 so as to lock and unlock the relative sliding of these two latter elements.

Therefore, there is a mechanism for locking/unlocking the relative position between the inner body 4 and the valve-guiding slider 1 1 , comprising a first ball race 24 housed in special seats 25 fashioned through the inner body 4 and in two annular grooves 26 and 27 fashioned on the valve- guiding slider 1 1 and the external slider 22, respectively, and inside of which the balls are engaged in a removable manner.

The chamber 21 containing the second spring 20 and the external slider 22 is sealed, and therefore it is not affected by the passage of the working fluid. The risk of the movement of the external slider and the operation of the overall locking/unlocking mechanism being jeopardised by deposits of sediment is thus reduced. Moreover, the system structured in this manner avoids having members liable to deterioration and/or metal residue come in contact with the fluid circulating in the hydraulic system, thus keeping the working fluid clean.

This sealing is realised by two seals 30 located at the intrados of the inner body 4, between the latter and the valve-guiding slider 1 1 , as shown in Figure 1 .

These two seals 30 are located at opposite ends along the axial direction with respect to the first ball race 24. A similar locking and unlocking mechanism is provided between the inner body 4 and the outer body 3 and it comprises a second ball race 28, interposed between the outer body 3 and the inner body 4, each ball being located in a respective hole 29 made through the front portion 4a of the inner body 4. At least one annular groove 38 is afforded on the inner surface of the head portion 3a of the outer body 3. The balls 28 engage inside the annular groove 38 so as to lock the relative sliding of the inner body 4 with respect to the outer body 3, when the male element 6 is engaged in the female body 2.

An additional annular groove 39 is suitable for receiving the balls 28 so as to free the axial movement of the male element 6 in the disengagement stage.

Advantageously, there are three seals in hydrodynamic equilibrium and they act in a sealed and sliding manner on respective circular surfaces having diameters that differ one from the other.

The three seals comprise a first seal 5a positioned between the inner body 4 and the fixed abutment element 15, which is internal to the axial channel 8 and rigidly connected to the outer body 3 through the terminal portion 3b. More specifically, the first seal 5a, which is preferably housed in a first groove 43 formed outside the fixed abutment element 15, acts in sliding contact on the intrados of the inner body 4, that is, on the inner surface of the inner body 4.

The second 5b and the third 5c seals are located on the extrados, hence on the outer surface, of the inner body 4, between the latter and the outer body 3.

Specifically, the second seal 5b is interposed between the first 5a and the third 5c seal, in a groove 44 formed inside the outer body 3. The second seal 5b acts in sliding contact on the extrados of the inner body 4.

The third seal 5c is housed in a groove 45 formed outside the inner body 4 and it acts in sliding contact on the intrados of the outer body 3.

Moreover, as can be seen in Figure 1 attached herein, the three seals are arranged at different distances from the axis 2a; in particular, the first seal 5a acts on a circular surface of a smaller diameter than the diameters of the circular surfaces on which the other two seals 5b, 5c act. The second seal 5b acts, in turn, on a circular surface of a diameter smaller than the diameter of the circular surface on which the third seal 5c acts.

There is at least one duct 35 afforded in the valve-guiding slider 1 1 , said duct 35 enabling the passage of fluid inside the axial channel 8, from the zone located at the rear with respect to the valve-guiding slider 1 1 to the shutter 10 zone. There is also at least one cavity 37 defined in the valve- guiding slider 1 1 , said cavity 37 leading into a passage 37a realised in the inner body 4 to bring the working fluid from the axial channel 8 to a chamber 36 interposed between the inner body 4 and the outer body 3, and between the second 5b and the third 5c seal. The working fluid under pressure fills this chamber 36, thereby pushing the second 5b and the third 5c seal, in opposite directions.

From the axial channel 8, however, the working fluid directly pushes the first seal 5a, passing between the valve-guiding slider 1 1 and the abutment element 15, thereby determining a thrust concurrent with the thrust exerted on the second seal 5b. Given that the third seal 5c exerts its action on the circular surface having a diameter greater than that of the circular surfaces on which the first 5a and the second 5b seal act, it shall also have a greater modulus and a direction opposite the thrusts exerted on the other two seals. Therefore, the sum of these forces considered in terms of modulus and direction is substantially equal to zero.

As shown in Figure 2, the coupling 1 can advantageously also have a discharge valve 31 for discharging residual pressure that may be present inside the female body 2.

In fact, the coupling may have residual pressure inside the axial channel 8, which, as mentioned previously, can obstruct or prevent coupling with the male element 6. This residual pressure must necessarily be eliminated by discharging part of the working fluid remaining under pressure inside the female element.

With this aim, the above-mentioned discharge valve 31 , which is observable in Figure 2, can be arranged in the terminal portion 3b of the outer body 3, or more generally, at the end of the axial channel 8.

This valve 31 enables the passage of the working fluid under pressure from the axial channel 8 to a drainage chamber 46, in fluid communication with the outside environment by means of a discharge duct 32 realised through the outer body 3, particularly in the terminal portion 3b.

The valve 31 comprises a shutter 48 that normally keeps the valve 31 closed and prevents the passage of working fluid from the axial channel 8 to the drainage chamber 46. When it is necessary to reduce the pressure inside the female element 2, the shutter is moved by the inner body 4, particularly by a rear end thereof, causing the shutter 48 to move backwards, which thus opens the valve 31 , enabling part of the working fluid remaining inside the female element to flow out, through the discharge duct 32.

In the case of a coupling without a discharge valve 31 , this discharge duct 32 can be closed by a simple locking ring nut 34a. However, in the case of a coupling with a discharge valve 31 , the ring nut 34 is of a sealing type and it has an outlet channel 34b for draining the working fluid at excess pressure to the outside environment.

The specific arrangement of the seals 5a, 5b e 5c in hydrodynamic equilibrium has made it possible to obtain a terminal portion 3b of the outer body 3 that is adaptable to couplings not having a discharge valve 31 and to couplings that require this valve 31 .

In fact, having moved the first seal 5a to the intrados of the inner body 4, has made it possible to obtain a zone 33 on the terminal portion 3b for housing the discharge valve 31 , at the shoulder of this terminal portion 3b located at the end of the axial channel 8.

Operation of this quick coupling 1 is as follows.

The male element 6, which is inserted inside the socket section of the female element 2, abuts against the shutter 10 and must overcome the thrust force exerted by the springs 13 and 14.

In the rest configuration, the first ball race 24 keeps the valve-guiding slider 1 1 and the inner body 4 solidly constrained one to the other. In fact, the ball race 24 is housed in the groove 26 afforded on the outer surface of the valve-guiding slider 1 1 .

The insertion of the male element 6 brings about the backward movement of the entire inner body 4, and thus of the valve-guiding slider 1 1 , towards the terminal portion 3b of the outer body, while the entire outer body 3 remains stationary.

In the particular case of a coupling equipped with a discharge valve 31 , the insertion of the male element 6, and the resulting backward movement of the entire inner body 4, causes the activation of this valve 31 following the interference of the inner body 4 with the shutter 48 of the valve 31 . The inner body 4 brings about a movement of the shutter 48 from the closed position thereof, thus opening the valve 31 , which sets the axial channel 8 in fluid communication with the discharge duct 32 through the drainage chamber 46. In this manner, the residual excess pressure inside the female element 2, which prevents the connection thereof with the male element 6, is eliminated by the partial outflow of the working fluid to the external environment.

Following the above-mentioned relative sliding between the inner body 4 and the outer body 3, the first ball race 24 translates with the inner body 4, reaching the groove 27 afforded on the inner surface of the external slider 22. When the balls in the first race 24 reach this latter groove 27, they can disengage from the groove 26 of the valve-guiding slider 1 1 , thereby enabling the relative sliding of the latter with respect to the inner body 4. Following further movement of the valve-guiding slider 1 1 , the balls 24 move radially outwards, pushed by the outer surface of the valve-guiding slider 1 1 .

In this situation, the shutter 10 is shifted from its closed position. Following the insertion of the male element 6 in the inner body 4 and the resulting translational movement of the latter, the second ball race 28 also slides inside the axial channel 8, reaching the innermost groove 38 afforded on the inner surface of the head portion 3a of the outer body 3. In this manner, the outer surface of the male element 6 radially pushes the second ball race 28 outwards and the ball race 28, upon engagement inside the groove 38, temporarily constrains the outer body 3 to the inner body 4, until the male element 6 positions one of its annular grooves 47 under the ball race 28, thereby enabling the latter to retract radially once again through the respective perforated seats 29 so as to lock the male element 6 to the inner body 4.

The radial re-entry of the balls 28 is assisted by the action of the spring 16, which provides for pushing the inner body 4 in a direction opposite the direction of insertion of the male element, preventing further radial movements of the second ball race 28.

Following counter-pressure from the female element 2, the contrasting force exerted by the male element 6 is overcome and fluid communication between the female element 2 and the male element 6 is realised.

The shutter 10 of the female element 2 translates for a given distance towards the closed position, without, however, closing the valve 9 completely, until it reaches an equilibrium of forces with the counterpart component 49 that is elastically supported in the male element 6.

This axial movement of the shutter 10 also involves a translational movement of the valve-guiding slider 1 1 , which thus repositions its annular groove 26 under the first ball race 24, which, by insertion in this groove 26, by effect of the thrust exerted by the spring 20, lock the first ball race 24 once again between the inner body 4 and the valve-guiding slider 1 1 . This latter position of the first ball race 24 is maintained following the final translational movement of the external slider 22 towards the terminal portion 3b, thus closing the first ball race 24 inside the groove 26.

The invention described herein achieves the proposed aims. In fact, as stated hereinabove, the particular arrangement of the seals and the dimensioning thereof have made it possible to obtain a coupling that is hydrodynamically balanced and versatile, that is, adaptable to the various needs of the user.

The positioning of the first seal on the intrados of the inner body has made it possible to obtain a zone in the terminal portion of the outer body that is suitable for housing a discharge valve as well, if required, without having to increase the overall dimensions of the coupling.

With the coupling constituting the object of the present invention, it is advantageously possible to realise standard components, which are not differentiated structurally according to the type of coupling, unlike prior art solutions.

In other words, a coupling equipped with a valve has exactly the same structurally identical components as those present in a coupling without a valve. The only difference between the two types of couplings is precisely the presence or absence of the valve, which is housed in a specific seat fashioned inside the terminal portion of the outer body.

This seat can be advantageously realised in all terminal portions already in the production stage, regardless of the type of coupling on which the terminal portion will be mounted, or fashioned later, in the assembly stage only in the case in which the coupling requires the valve.

Therefore, the only component that could eventually differ in the case of the two types of couplings is the terminal portion of the outer body, while all other components are common to both types.

It is thus possible to keep only one type of component in stock, and, if necessary, apply only the valve at the terminal portion of the outer body, if requested by the user.

In this manner, simpler and more economical management of the inventory in stock is achieved, in addition to simplification of the stages involving the design, industrialisation and realisation of couplings of different types.

Claims

1 . A quick coupling for hydrodynamic systems comprising:

a female element having an outer body (3) and an inner body (4) associated in a sealed manner with the outer body (3) by a plurality of seals (5a, 5b, 5c) in hydrodynamic equilibrium with each other; said inner body (4) being relatively translatable with respect to said outer body (3); an axial channel (8) formed inside said inner body (4) and extending for the entire length of the female element (2);

a valve (9), positioned inside said axial channel (8), comprising a shutter (10) supported by a respective valve-guiding slider (1 1 ) that is slidable inside said axial channel (8),

characterised in that at least a first seal (5a) of said seals (5a, 5b, 5c) is located at the intrados of said inner body (4).

2. The quick coupling according to claim 1 , characterised in that said seals (5a, 5b, 5c) act on circular surfaces having different diameters.

3. The coupling according to claim 1 or 2, characterised in that said seals (5a, 5b, 5c) in hydrodynamic equilibrium comprise a second (5b) and a third seal (5c) located on the extrados of said inner body (4), between said inner body (4) and said outer body (3).

4. The coupling according to claim 3, characterised in that said second seal (5b), interposed between said first (5a) and said third seal (5c), acts on the extrados of said inner body (4), whilst said third seal (5c) acts on the intrados of said outer body (3).

5. The coupling according to any one of the preceding claims, characterised in that said first seal (5a) acts on a circular surface having a smaller diameter than the diameters of the circular surfaces on which said second (5b) and said third seal (5c) act, respectively.

6. The coupling according to claim 5, characterised in that said second seal (5b) acts on a circular surface of a diameter smaller than the diameter of the circular surface on which said third seal (5c) acts.

7. The coupling according to any one of the preceding claims, characterised in that said first seal (5a) is positioned between the inner body (4) and a fixed abutment element (15), which is internal to the axial channel (8) and rigidly connected to the outer body (3).

8. The coupling according to any one of the preceding claims, characterised in that it comprises at least two additional seals (30) located on the intrados of said inner body (4), between said inner body (4) and said slider (1 1 ) supporting said shutter (10), for hydraulically isolating a sealed chamber (21 ), located between said inner body (4) and said outer body (3).

9. The coupling according to the preceding claim, characterised in that it comprises a mechanism for locking/unlocking the relative position between said inner body (4) and said valve-guiding slider (1 1 ) supporting said shutter (10); said locking/unlocking mechanism being at least partly contained in said sealed chamber (21 ).

10. The coupling according to any one of the preceding claims, characterised in that said outer body (3) comprises, at one respective end, a terminal closing portion (3b) connectable to a distributor or to a hydrodynamic circuit.

1 1 . The coupling according to claim 10, characterised in that said terminal closing portion (3b) comprises a discharge valve (31 ) for discharging residual pressure that may be present inside the female element (2).

12. The coupling according to claim 10 or 1 1 , characterised in that said terminal closing portion (3b) comprises a discharge duct (32) extending between the outside environment and a drainage chamber (46) formed between the terminal closing portion (3b) and a fixed abutment element (15), inside the axial channel (8).

13. The coupling according to claims 1 1 and 12, characterised in that said discharge valve (31 ) is operatively interposed between the drainage chamber (46) and the axial channel (8).