QUICK-CONNECTING COUPLING ASSEMBLY INCLUDES A LOCKING PISTON CONNECTED WITH LOW PRESSURE LOSS
Patent Information
- Authority / Receiving Office
- VN · VN
- Patent Type
- Applications
- Current Assignee / Owner
- STUCCHI SPA
- Filing Date
- 2024-09-27
- Publication Date
- 2026-07-01
AI Technical Summary
Existing quick coupling assemblies for hydraulic lines face challenges in preventing connection when pressure exceeds a threshold value, leading to potential unsafe movements of equipment, and suffer from complex calibration, rapid gasket wear, and significant load drops in fluid flow.
A quick coupling assembly with a full piston that moves radially and is actuated by pressure acting directly on its bottom, without through cavities, and is designed to prevent connection when pressure exceeds a threshold value, while allowing disconnection in any case and optimizing the fluid path to reduce load drops.
The solution effectively prevents connection at high pressures, allows safe disconnection, simplifies maintenance, and significantly reduces load drops in fluid flow, improving the overall safety and efficiency of hydraulic connections.
Smart Images
Figure VN1202603805_0
Abstract
Description
[0001] "Quick coupling assembly with connection locking piston and low loss of load"
[0002] * * * *
[0003] The present invention relates to a quick coupling assembly with connection locking piston and low loss of load.
[0004] The use of quick coupling assemblies suitable for connecting hydraulic lines under pressure with fluid (industrial oil) working pressure that does not exceed 300 bars is widespread in the agricultural machinery industry.
[0005] The quick coupling assembly comprises a female coupling and a male coupling, wherein the male coupling is suitable for fitting into the female coupling which is associated with a machine, e.g. a tractor, while the male coupling is associated with an equipment, e.g. a weeder, to be connected to the machine.
[0006] When the machine is on, there is a minimum pressure (about 10 bar) in the hydraulic system of the machine, and thus in the female coupling. For safety reasons, regulations require that it be not allowed to connect the male coupling to the female coupling with said or higher pressure because otherwise said pressure would be transmitted to the equipment, which could move inadvertently.
[0007] For example, when the machine is off, the system pressure remains below 10 bars. In said case, the connection between the male coupling and female coupling is allowed.
[0008] US-2020 / 0332937 describes a quick coupling assembly comprising a female coupling and a male coupling, wherein the male coupling is suitable for being inserted into the female coupling making a pressurized hydraulic connection between the female coupling and the male coupling.
[0009] The female coupling comprises an external body fixed to a machine, e.g. a tractor, and an internal body sliding axially into a cavity in the external body.
[0010] The female coupling comprises a head, in which the connection to the male coupling occurs, and a back, in which connection to the machine occurs.
[0011] The female coupling further comprises a piston suitable for moving radially, i.e. in a direction orthogonal to the axis of the quick coupling assembly along which the connection movement between the female coupling and the male coupling takes place.
[0012] The piston is suitable for moving between a first position, in which the connection between the female coupling and the male coupling is permitted, and a second position, in which said connection is prohibited.
[0013] The piston comprises a head and a stem. A hole passing along the axis of the piston, i.e. in said radial direction of the assembly, passes through both the head and the stem. There are two gaskets between the piston and the side walls of its seat, one on the head and one on the stem. The through-hole puts the cavity of the female coupling into fluid communication with a chamber located above the piston head.
[0014] With reference to the axis of the quick coupling assembly, the piston head is wider than the stem. Under the head, around the upper end of the piston stem, there is a spring which acts in the direction of the piston axis, in particular, it biases the piston to move towards the outside of the female coupling, i.e. it tends to reduce the protrusion of the lower end of the piston stem into the cavity of the female coupling.
[0015] A pressure exhaust channel is in communication with the bottom of the piston head, where the spring is located.
[0016] The piston moves along its axis as a function of the difference in force induced by the spring (outward thrust) and the hydraulic pressure (inward thrust) on the piston head.
[0017] The spring is calibrated so that beyond a pressure threshold value in the female coupling cavity, the piston moves into the second position, i.e. towards the inside, preventing the sliding of the internal sliding body of the female coupling; the connection between the female coupling and the male coupling cannot take place. If the pressure in the female coupling cavity is below said threshold value, the piston is in said first position; the connection between the female coupling and the male coupling can take place.
[0018] Disadvantageously, the calibration of the spring is very complex; the dimensions of the stem and the head must be taken into account with accuracy.
[0019] Furthermore, the spring seat is very small because the female coupling cavity must have sufficient space for the internal female coupling body to slide. Consequently, it is not possible to mount springs with excessive load, i.e. the piston can remain in a useful position for connection only for low pressure values, lower than 10 bars of normal use.
[0020] Finally, two gaskets must be provided, one on the head and one on the stem; disadvantageously, wear rapidly reduces the precision of the piston actuation. The replacement of the gaskets and the spring is very complicated.
[0021] WO-2022 / 248350, by the applicant, describes a quick coupling assembly suitable for connecting hydraulic lines under pressure, comprising a female coupling and a male coupling connectable with the female coupling, wherein the female coupling is associable with a machine suitable for generating hydraulic pressure, while the male coupling is associable with an equipment.
[0022] The female coupling comprises an external part, which may be fixed to the machine, a piston, and an internal part, sliding along a connection axis inside the external part, wherein the connection axis defines an axial direction.
[0023] The external part and the internal part are shaped to create an axial chamber suitable for maintaining the hydraulic pressure generated by the machine. The external part comprises a radial seat for the piston suitable for moving radially between a first position, in which the connection between the female coupling and the male coupling is allowed, and a second position, in which the connection between the female coupling and the male coupling is forbidden due to the interference between the internal part and the piston.
[0024] The piston assumes the second position when there is a hydraulic pressure equal to or greater than a threshold value in the female coupling.
[0025] The piston comprises a head and a stem, wherein the head provides a lateral seat for a gasket suitable for guaranteeing the seal between the axial chamber and a chamber housing a spring suitable for forcing the piston into the first position, wherein the chamber housing the spring is in hydraulic connection with an exhaust duct.
[0026] The piston is a full piston without through cavities.
[0027] Compared to the assembly described in US-2020 / 0332937, the hydraulic pressure which pushes the full piston into the second position, the locking position, acts in only one direction, completely over the full piston head. Only the spring acts in the opposite direction.
[0028] The sizing of the full piston and spring is simpler, having to consider in practice only the dimensions of the full piston in its radial seat.
[0029] Maintenance is simplified because there is a single seal on the full piston, i.e. the gasket on the external edge of the head.
[0030] However, the thrust able to move the full piston to the locking position occurs due to a conformation of the axial chamber which provides oblique chambers suitable for diverting the axial flow of the fluid under pressure, from the center outward. The locking thrust acts from the outside toward the connection axis, from an external chamber of the axial chamber, between the external and internal parts of the female coupling.
[0031] Disadvantageously, said diversion causes a load drop in the fluid flow, which increases with the size of the assembly.
[0032] US-2007 / 246108 describes a quick coupling assembly with a locking piston upon the disconnection of a male coupling from a female coupling in the case of a hydraulic pressure equal to or greater than a threshold value. The connection and disconnection are controlled by an external ring nut sliding in the direction of the connection axis and disconnection axis.
[0033] US-9528650, of the same family as JP -2014 / 185773, describes a quick coupling assembly with a locking piston upon connection and disconnection of a male coupling from a female coupling in the case of a hydraulic pressure equal to or greater than a threshold value. The connection and disconnection are controlled by an external ring nut sliding in the direction of the connection axis and disconnection axis.
[0034] Disadvantageously, US-2007 / 246108 and US-9528650 are not suitable for use in the agricultural sector because they do not allow the disconnection in case the pressure is above the threshold value.
[0035] It is the object of the present invention to make a quick coupling assembly suitable for connecting hydraulic lines under pressure, comprising a female coupling and a male coupling suitable for inserting into the female coupling, wherein a piston is provided which prohibits the connection in case of pressure exceeding a threshold value, wherein said piston is full without through cavities and moves in a radial direction, i.e. orthogonally relative to the axial connection direction between the female coupling and the male coupling, the disconnection being allowed in any case.
[0036] It is a further object of the present invention for the piston to be easy to actuate and maintain the actuating threshold value over time.
[0037] It is a yet further object of the present invention to reduce the load drops in the fluid flow under pressure in the assembly by optimizing the pressurized fluid path.
[0038] According to the invention, said and further objects are achieved by a quick coupling assembly suitable for connecting hydraulic lines under pressure, as defined in claim 1.
[0039] Advantageously, compared with the solution proposed by the present applicant in WO-2022 / 248350 wherein, in any case, a full locking piston movable in the radial direction is provided, a substantial reduction in load drop is achieved because the flow of the pressurized fluid is free from diversions in the radial direction because the thrust of the full piston in the locking position occurs by acting on the bottom of the full piston, i.e. a part of the full piston which faces directly into the axial chamber near the connection axis.
[0040] Comparative technical tests showed an almost halved load drop. The improvement was made possible by virtue of the different conformation of the external and internal parts of the female coupling. The radial seat of the full piston is in the internal part instead of the external part. This allows a direct action of the fluid under pressure flowing centrally in the axial chamber near the connection axis, without diversions which cause load drops in the solution of WO-2022 / 248350.
[0041] These and other features of the present invention will become more apparent from the following detailed description in practical embodiments thereof illustrated by way of non-limiting example in the accompanying drawings, in which: figure 1 shows a side view of a quick coupling assembly according to the present invention, wherein a male coupling is separated from a female coupling; figure 2 is a rear view of the assembly; figure 3 shows a section view taken along line III-III in figure 2; figure 4 shows a section view taken along line IV-IV in figure 1; figure 5 shows the enlarged content of circle A in figure 3; figure 6 shows the enlarged content of circle B in figure 3; figure 7 shows a section view similar to the one in figure 3, in a first connection position, in which there is a pressure in the female coupling which is lower than a threshold value; figure 8 shows a section view similar to the one in figure 3, in a second connection position, in which there is a pressure in the female coupling which is lower than the threshold value; figure 9 shows a section view similar to the one in figure 3, in a third connection position, in which there is a pressure in the female coupling which is lower than the threshold value; figure 10 shows a section view similar to the one in figure 3, in a fourth connection position, in which there is a pressure in the female coupling which is lower than the threshold value; figure 11 shows a section view similar to the one in figure 3, in a fifth connection position, in which there is a pressure in the female coupling which is lower than the threshold value; figure 12 shows a section view similar to the one in figure 3, in a sixth connection position, in which there is a pressure in the female coupling which is lower than the threshold value; figure 13 shows a section view similar to the one in figure 3, in a seventh connection position, in which there is a pressure in the female coupling which is lower than the threshold value; figure 14 shows a section view similar to the one in figure 3, in an eighth connection position, in which there is a pressure in the female coupling which is lower than the threshold value; figure 15 shows a section view similar to the one in figure 3, in a complete connection position, in which there is a pressure in the female coupling which is lower than the threshold value; figure 16 shows a section view similar to the one in figure 3, in a first disconnection position, in which there is a pressure equal to or greater than the threshold value in the female coupling; figure 17 shows a section view similar to the one in figure 3, in a second disconnection position, in which there is a pressure equal to or greater than the threshold value in the female coupling; figure 18 shows a section view similar to figure 3, in which the connection is prohibited because there is a pressure equal to or greater than the threshold value in the female coupling; figure 19 shows the enlarged content of circle C in figure 18.
[0042] A quick coupling assembly 1 suitable for connecting pressurized hydraulic lines according to the present invention comprises a female coupling 2 and a male coupling 3 connectable with the female coupling 2 (figure 1).
[0043] The female coupling 2 is associable with a machine (not shown), e.g. a tractor, while the male coupling 3 is associable with an equipment (not shown), e.g. a weeder or vice versa.
[0044] With particular reference to figures 3 and 4, the female coupling 2 comprises an external part 4 which can be fixed to the machine, at least one full piston 26 and an internal part 5 sliding along a connection axis X inside the external part 4, wherein the connection axis X defines an axial direction.
[0045] The external part 4 of the female coupling 2 comprises a junction 6 for connecting to the machine, a female body 7 and a ring nut 8 integral with each other. More in particular, the ring nut 8 is screwed to the female body 7 which in turn is screwed to the junction 6 which is connected to the machine, e.g. by threading, so that it is integral to the machine allowing the passage of fluid (industrial oil) under pressure through said junction 6. Consequently, the junction 6, the female body 7, and the ring nut 8 form a single body, i.e. the external part 4, which does not move with respect to a machine coupling which connects with the junction 6 of the female coupling 2.
[0046] The internal part 5 of the female coupling 2 comprises a sliding body 9, a shutter 10 and a ring nut holder 11 suitable for containing balls 12 in respective seats 111. The ring nut holder 11 is screwed to the sliding body 9, i.e. it is integral therewith, thus allowing the movement of the balls 12 as will become clearer later.
[0047] The sliding body 9 is associated with a pressure relief valve 17.
[0048] The shutter 10 has a head 101 and a stem 102, wherein the head 101 is in one piece with the stem 102. The head 101 comprises a flat end 103 facing the male coupling 3; the head 101 expands radially toward the flat end 103.
[0049] A spring 14 is provided between the external part 4 and the internal part 5 suitable for keeping the female coupling 2 in the resting position when it is separated from the male coupling 3.
[0050] A cup 15, which is held in place by a spring 16, is suitable for sliding inside the ring nut holder 11. The cup 15 comprises a thrust portion 155 suitable for moving the balls 12 at least partially into an exhaust seat 81 of the ring nut 8.
[0051] The internal part 5 also comprises a sleeve 50 through which the stem 102 of the shutter 10 passes. The sleeve 50 is suitable for sliding axially, i.e. along the connection axis X, relative to both the sliding body 9 and the shutter 10.
[0052] The sleeve 50 has an end 51 which interacts in a sealing manner with the head 101 of the shutter 10, wherein a spring 53 is suitable for forcing said seal. The sleeve 50 comprises a radial thickness 52 suitable for receiving in abutment a complementary thickness 151 of the cup 15 which is suitable for overcoming the seal of the sleeve 50 on the shutter 10 as will be explained in greater detail below.
[0053] The pressure relief valve 17 is associated with the internal part 5, in particular with the sliding body 9, even more in particular with a rear portion 91 of the sliding body 9. Preferably, the rear portion 91 is a separable body from a front portion 92 of the sliding body 9, the connection being preferably screwed.
[0054] The external part 4 and the internal part 5 are shaped to form a single chamber 18 in which a working pressure of the machine transmitted by the equipment is present, typically of at least 10 bars up to a maximum of 300 bars. Working pressure is defined as the pressure suitable for actuating the equipment.
[0055] The rear portion 91 provides a radial seat 25 for the full piston 26 (figure 5).
[0056] It is worth noting that radial means a direction orthogonal to that of the connection axis X.
[0057] The rear portion 91 and the female body 7 are shaped to form a locking seat 200.
[0058] The full piston 26 comprises a head 261, a stem 262 and bottom 265. Full piston 26 means a piston with a full head and stem, i.e. without through cavities, in particular without a through cavity along the radial direction in which the full piston 26 moves, between the head 261 of the full piston 26 and the bottom 265 of the full piston 26.
[0059] A spring 27 embraces the full piston 26 in a chamber 29 of the radial seat 25 and is adapted to push an annular thickness 267 of the full piston 26 onto an abutment 911 of the rear portion 91, the spring 27 acting radially between said annular thickness 267 and a ring 271 integral with the rear body 91.
[0060] An upper surface 263 of the head 261 of the full piston 26 is suitable for facing the locking seat 200.
[0061] The bottom 265 of the full piston 26 has a lateral seat 264 for a gasket 28 suitable for ensuring the seal between the axial chamber 18 and the chamber 29 of the radial seat 25, wherein said chamber 29 is in communication with the locking seat 200.
[0062] It is worth noting that the chamber 29 is in communication with locking seat 200, meaning that there is no seal between the chamber 29 and the locking seat 200, seal which is between the axial chamber 18 and the chamber 29 instead.
[0063] As mentioned above, the full piston 26 has no through cavities, i.e. between axial chamber 18 and locking seat 200 there is a pressure seal by virtue of the gasket 28, which then prevents the pressurized hydraulic fluid which flows in axial chamber 18 from entering into the chamber 29 and thus into the locking seat 200.
[0064] The pressure relief valve 17 is suitable for selectively connecting a pressure relief chamber 900, in hydraulic connection with the axial chamber 18 by means of a gap 901, with an exhaust duct 30 (figure 6).
[0065] The pressure relief valve 17 comprises a shutter 171 axially movable between a closing position in which the pressure relief chamber 900 and the exhaust duct 30 are sealed apart, and a pressure relief position in which the pressure relief chamber 900 is in hydraulic connection with the exhaust duct 30. The pressure relief position is reached as a result of one end 173 of the shutter 171 abutting against a radial wall 300 of the external part 4. Pressure relief also occurs due to the shape of the shutter 171 which comprises a narrow central portion 172.
[0066] The full piston 26 is suitable for sliding between a first position (figure 5) in which the head 261 of the full piston 26 does not protrude into the locking seat 200, and a second position (figure 19) in which the head 261 protrudes into the locking seat 200.
[0067] The male coupling 3 (figures 3 and 4) comprises a male body 70, a shutter 71 sliding axially into the male body 70, and a junction 72 suitable for connecting to the equipment (not shown).
[0068] The shutter 71 is also suitable for sliding relative to an internal body 76 housed in and integral with the male body 70.
[0069] A spring 73 holds a head 74 of the shutter 71 in a sealing manner on the male body 70, while an internal valve 75 is suitable for putting the male coupling 3 into fluid communication with the equipment (not shown).
[0070] The radial ends of the shutter 71 and the male body 70 of the male coupling 3 form a flat face of the male coupling 3.
[0071] The ends of the shutter 10 and the cup 15 of the female coupling 2 form a flat face of the female coupling 2.
[0072] By observing the figures 7-15 in sequence, it is possible to understand how the connection occurs if the pressure in the axial chamber 18 is below a threshold value, e.g. when the machine is off, i.e. if the connection between the female coupling 2 and the male coupling 3 is allowed.
[0073] The threshold value preferably coincides with the minimum working pressure of the machine, i.e. the pressure for actuating the equipment connected by means of the assembly 1, typically 10 bars. As already mentioned, if the machine is turned on and the male coupling 3 is disconnected from the female coupling 2, the pressure in chamber 18 is greater than 10 bars and thus the connection could cause sudden and unwanted movements of the equipment generating dangerous situations.
[0074] Highlighting that a flat-face type assembly 1 is being described, when the flat face of the male coupling 3 is pushed (by an operator) against the flat face of the female coupling 2, the two shutters 10, 71 come into contact as well as the male body 70 with the cup 15 (figure 7).
[0075] The male body 70 axially pushes the cup 15 backwards (toward the bottom of the female coupling 2, i.e. leftwards when looking at figures 7-15), which moves the balls 12 from their seats 111 so as to move toward (figure 8- 10) or at least partially occupy (figure 11) the exhaust seat 81 of the ring nut 8.
[0076] Figure 8 shows the thrust thickness 155 of the cup 15 which, having passed the balls 12, begins to push the balls 12, in the ring nut holder 11, toward the exhaust seat 81.
[0077] In figure 10, the balls 12 still partially occupy respective seats 156 of the cup 15 but already face the exhaust seat 81.
[0078] In the position of figure 11, the balls 12 no longer protrude partially into the seats 156 of the cup 15 but partially occupy the exhaust seat 81 allowing the male body 70 to push the cup 15 further back without interfering with the balls 12.
[0079] Residual pressure is present in the axial chamber 18, e.g. 5 bars, which the pressure relief valve 17 exhausts as follows.
[0080] As seen in figure 11, the position of the balls 12 at least partially in the exhaust seat 81 allows the cup 15 to also push back the sliding body 9 until the end of the shutter 171 of the pressure relief valve 17 touches the radial wall 300 of the external part 4 initiating the residual pressure relief which continues in figure 12 in which the cup 15 is further retracted so that the balls 12 no longer face into the seats 156 of the cup 15.
[0081] The thrust of the cup 15 is opposed to a ring nut spring 82 which acts on the ring nut holder 11 through a thickness 112 (figure 12). Once the balls 12 are in the exhaust seat 81 of the ring nut 8, the ring nut holder 11 is in a stable position in which the forward thrust (to the right as seen in figure 12) of the ring nut spring 82 is balanced by the contrast exerted by the exhaust seat 81 of the ring nut 8.
[0082] Continuing the insertion of the male body 70 into the female coupling 2, in particular sliding inside the ring nut holder 11 (figures 13, 14), the radial thickness 151 of the cup 15 comes into contact with the radial thickness 52 of the sleeve 50 which retracts thus opening the hydraulic line between the female coupling 2 and the male coupling 3. The balls 12 leave the exhaust seat 81 of the ring nut 8, pushed by the ring nut spring 82, and partially fit into an external seat 90 of the male body 70.
[0083] To make the connection stable (in figure 14, it can be seen that the balls 12 are still facing the exhaust seat 81), the sliding body 9, fed by the ring nut holder 11 , moves forward (rightwards looking at the figures) taking the shutter 171 of the pressure relief valve 17 back to the closing position (figure 15). The connection is complete, stable and secure.
[0084] In the absence of pressure above the threshold value in the axial chamber 18, i.e. with machine off, the full piston 26 is held in the first position without interfering with the connection between the female coupling 2 and the male coupling 3.
[0085] If the pressure in the axial chamber 18 is greater than the threshold value (figures 18, 19), i.e. if the machine is on, always starting from a situation of a male coupling 3 separated from the female coupling 2 as in figures 3, 4, even before starting the connection attempt, the full piston 26 slides in the second position in this way preventing the axial sliding of the male coupling 3 in the female coupling 2.
[0086] Consequently, if the operator tries to force the insertion of the male coupling 3 into the female coupling 2, at a given point it will find a lock generated by the head 261 of the full piston 26 which abuts onto a radial wall 201 of the locking seat 200. As the sliding body 9 cannot retract further, the cup 15 does not interact with the sleeve 50 which thus remains sealed to the head 101 of the shutter 10.
[0087] If the overpressure in female coupling 2 is not relieved, e.g. by switching off the machine, the connection between the male coupling 3 and the female coupling 2 cannot take place.
[0088] Once the connection has taken place, turning on the machine generates pressure above the threshold value, i.e. during the actuation of the equipment under normal operating conditions, the full piston 26 is in the second position.
[0089] Figures 16 and 17 show the possibility of disconnection in the case of overpressure (pressure above the threshold value), i.e. even if the full piston 26 is in the second position it is always possible, for safety reasons (e.g. fire), to disconnect the male coupling 3 from the female coupling 2.
[0090] As apparent by observing figure 16, the locking seat 200 is shaped to allow the full piston 26, in the second position, to still move rightwards, i.e. in the disconnection direction of the male coupling 3 from the female coupling 2. After the connection, with the assembly 1 operating at the working pressure, the internal part 5, to which the full piston 26 is integral in the direction of the coupling (disconnection) axis X, can move in the disconnection direction X with respect to the external part 4, in which the locking seat 200 is made, which provides sufficient space for the movement of the full piston 26, in the second position, in the disconnection direction.
[0091] In any condition, the disconnection is accomplished simply by pulling the male coupling 3 in the outlet direction from the female coupling 2, without any aid of release means such as in the aforementioned US-2007 / 246108 and US-9528650. The locking seat 200 is made in the external part 4 with a constant volume which is partially occupied by the head 261 of the full piston 26 when it is in the second position.
[0092] Advantageously, the pressure which pushes the full piston 26 into the second position, the locking position, acts in only one direction, completely on the lower surface 266 of the bottom 265 of the full piston 26.
[0093] Only the spring 27 acts in the opposite direction.
[0094] The seal between the chamber 29, i.e. of the radial seat 25 and the locking seat 200, and the axial chamber 18 is guaranteed by the gasket 28 on the lateral edge of the bottom 265 alone.
[0095] Advantageously, the sizing of the full piston 26 and spring 27 is simple, because in practice only the dimensions of the full piston 26 in its radial seat 25 need to be considered, with no through cavities complicating design calculations.
[0096] The radial seat 25 of the full piston 26 can be enlarged to use heavily loaded springs 27.
[0097] Maintenance is simplified because there is a single seal on the full piston 26, which is the gasket 28 on the external edge of the bottom 265.
[0098] Compared with the solution proposed by the present applicant in WO- 2022 / 248350 in which, in any case, a movable full locking piston is provided in the radial direction, a substantial reduction in load drop is achieved because the flow of the pressurized fluid is free from diversion in the radial direction as the thrust of the full piston 26 in the locking position occurs by acting on the bottom 265 of the full piston 26, i.e. a part of the full piston 26 which faces directly into the axial chamber 18 near the connection axis X.
[0099] For example, for a coupling according to the present invention measuring 3 / 4 inches (19 millimeters), a load drop value at the nominal flow rate of 100 1 / min (liters per minute) of 0.8 bar occurred.
[0100] The same test on a coupling of the same size as described in WO- 2022 / 248350, i.e. with flow diverted outward to push the full piston into the locking position from the outside inward, gave a load drop value of 1.4 bar.
[0101] The obvious improvement (load drop almost halved) is understood. Of course, values can change according to the size of the coupling and the flow rate, while remaining a similar improvement.
[0102] The improvement was made possible by the different conformation of the external part 4 and the internal part 5 of the female coupling 2.
[0103] The radial seat 25 of the full piston 26 is now in the internal part 5 instead of the external part 4. This allows a direct action of the fluid under pressure flowing centrally in the axial chamber 18 near the connection axis X, without diversions which cause load drops in the solution of WO- 2022 / 248350.
[0104] Advantageously, pressure relief is also simplified, the pressure relief valve 17 being in a lateral position and thus leaving the central flow of pressurized fluid unobstructed. The pressure relief valve 17 is associable with the internal part 5 in a different manner than described, but the shutter 171 must move axially in the connection direction of the male coupling 3 so that its end 173 touches a wall 300 of the external part 4, which is stationary as opposed to the moving internal part 5. The shape of the pressure relief chamber 900 and the exhaust duct 30 can also vary, their residual pressure relief function remaining as described above.
[0105] The shape of the full piston 26, in any case without through cavities, may also vary, it being essential that the head 261 is adapted for selectively at least protruding into the locking seat 200 in case of overpressure, and there is a lateral seat 264 for the gasket 28 suitable for realizing the essential pressure seal between the axial chamber 18 and the chamber 29, i.e. the locking seat 200.
[0106] It is worth noting that the described embodiment has a single full piston 26, but an assembly 1 with a plurality of full pistons 26 can be provided to make the connection locking more effective.
Claims
CLAIMS1. Flat face quick coupling assembly (1) suitable for connecting hydraulic lines under pressure, comprising a female coupling (2) and a male coupling (3) connectable to the female coupling (2), wherein the female coupling (2) is associated with a machine suitable for generating hydraulic pressure, while the male coupling (3) is associated with an agricultural equipment, wherein the female coupling (2) comprises an external part (4) fixed to the machine by means of a junction (6) so as to be integral with the machine allowing the passage of pressurized fluid through said junction (6), at least one full piston (26) without through cavities, and an internal part (5) sliding along a connection axis (X) inside the external part (4), wherein the connection axis (X) defines an axial direction, the external part (4) and the internal part (5) are shaped so as to create an axial chamber (18) suitable for maintaining the hydraulic pressure generated by the machine, wherein the full piston (26) is provided with a head (261), a stem (262) and a bottom (265), and is suitable for moving radially between a first position in which the connection between the female coupling (2) and the male coupling (3) is allowed, and a second position in which the connection between the female coupling (2) and the male coupling (3) is forbidden, wherein the full piston (26) assumes the second position when in the female coupling (2) there is a hydraulic pressure equal to or greater than a threshold value, thus preventing the connection between the male coupling (3) and the female coupling (2), wherein the full piston (26) comprises a lateral seat (264) for a gasket (28) suitable for guaranteeing the seal between the axial chamber (18) and a chamber (29) housing a spring (27) suitable for forcing the full piston (26) in the first position, characterized in thatthe full piston (26) is housed in a radial seat (25) of the internal part (5), wherein the external part (4) and the internal part (5) are shaped to form a locking seat (200) into which the head (261) of the full piston (26) is selectively suitable for entering as a function of the hydraulic pressure in the axial chamber (18), in said second position of the full piston (26) the head (261) of the full piston (26) being inside the locking seat (200) shaped to allow the disconnection between the male coupling (3) and the female coupling (2) in the case of previous connection with the full piston (26) in said second position, between the axial chamber (18) and the locking seat (200) there being a pressure seal thanks to the gasket (28) whose lateral seat (264) is on the bottom (265) of the full piston (26), the chamber (29) of the spring (27) being in the radial seat (25) and in communication with the locking seat (200).
2. Assembly (1) according to claim 1, characterized in that the spring (27) is suitable for pushing an annular thickness (267) of the full piston (26) onto an abutment (911) of the internal part (5), the spring (27) acting radially between said annular thickness (267) and a ring (271) integral with the internal part (5).
3. Assembly (1) according to claim 1 or 2, characterized in that it comprises a pressure relief valve (17) associated with the internal part (5) and suitable for selectively connecting a pressure relief chamber (900), in hydraulic connection with the axial chamber (18) via a gap (901), with an exhaust duct (30).
4. Assembly (1) according to claim 3, characterized in that the pressure relief valve (17) comprises a shutter (171) axially movable between a closed position in which the pressure relief chamber (900) and the exhaust duct (30) are sealed apart, and a pressure relief position in which the pressure relief chamber (900) is in hydraulic connection with the exhaust duct (30).
5. Assembly (1) according to claim 4, characterized in that the pressure relief position of the shutter (171) is reached following the abutment of one end (173) of the shutter (171) on a radial wall (300) of the external part (4),the shutter (171) comprising a narrow central portion (172).
6. Assembly (1) according to any of the preceding claims, characterized in that the external part (4) comprises, integral with each other, the junction (6) for connecting to the machine, a female body (7) and a ring nut (8), the internal part (5) comprises a sliding body (9), a shutter (10) and a ring nut holder (11) suitable for containing balls (12), wherein the radial seat (25) for the full piston (26) is obtained in the sliding body (9) to which the pressure relief valve (17) is associated.