VALVE FOR A SINGLE-ACTING CYLINDER AND ITS ASSEMBLY IN A MOTOR VEHICLE'S TIPPER BODY

Description

[0001] The invention relates to a valve for a hydraulic cylinder group, which is configured to control the oil flow to the hydraulic cylinder of such a group.

[0002] In a preferred, but not exclusive, embodiment, the valve is advantageously applied and placed on the outer jacket of a hydraulic cylinder actuating tipper bodies of vehicles known as "dump trucks". In more detail, the valves of this type are known and used to control the motion of a cylinder which lifts one side of the tipper body so as to discharge it.

[0003] An example of such an application is described in patent U.S. 4.182.534 which relates to a system for actuating hydraulic members in a vehicle that comprises a relief valve which includes one end that can be actuated via contact with a movable part of the hydraulic members. Examples of similar solutions are also described in DE 40 17 947 or FR 2 535 151.

[0004] These solutions are however difficult to install in conventional solution of vehicles provided with tipper bodies as they require a specific design of the conduits needed for the operation of the hydraulic and/or pneumatic circuits while preventing them from interacting improperly with the movable members.

[0005] The technical problem underlying the present invention is to provide a valve for a hydraulic cylinder group which allows overcoming the drawbacks mentioned above with reference to the prior art.

[0006] Moreover, within such a technical problem, an object of the present invention is to provide an improved valve for controlling the oil flow in a movable cylinder with a simple, rational and rather cost-effective solution.

[0007] A further object is to provide a valve that is versatile and simple in its installation on hydraulic cylinder groups and in general on the vehicle.

[0008] These and other objects are achieved with the features of the invention described in the independent claim 1. The dependent claims describe preferred and/or particularly advantageous aspects of the invention.

[0009] In particular, in one embodiment the valve comprises an associated limiting device adapted to interact, in turn, with one or more fixed abutment elements during the extension step of the cylinder, typically associated with the lifting of the vehicle's body, and then its relative rotation with respect to a rotation end pin, to which it is normally hinged.

[0010] As a result of the contact with the abutment element, the limiting device is actuated and, as a result of the actuation it sets a pneumatic delivery acting on the valve shutter in communication with the outside, thus interrupting the pneumatic supply.

[0011] The abutment elements for example are integrally placed on the same support structure as the cylinder rotation pin on which the valve of the present invention is applied. Based on this arrangement, the abutment element is fixed relative to the movement of the cylinder.

[0012] With this solution it is possible, by adequately placing the abutment, to block the cylinder stroke before reaching its maximum angle, thus limiting the stroke of the hydraulic cylinder.

[0013] In other words, the limiting device acts as a relief limiting valve of the cylinder stroke in lifting conditions, adapted to vent the pneumatic air once a predefined stroke has been reached by means of a fixed abutment.

[0014] Another aspect of the invention is to provide a cost-effective limiting device.

[0015] In one embodiment, the limiting device comprises an actuating element configured to interact with the abutment element and sliding in a respective seat.

[0016] Preferably, the actuating element is configured to control a respective stem through an interposed first spring.

[0017] According to a preferred embodiment, the actuating element, the first spring and the stem are arranged axially aligned in a same cavity of the device.

[0018] This solution allows an effective actuation of the actuating element and discharge of pressurized chamber of the shutter drive unit.

[0019] In one embodiment, the valve comprises a relief valve, placed longitudinally off axis and in hydraulic connection with the cylinder connection.

[0020] Preferably, the relief valve is configured to intervene when the pressure in the cylinder group exceeds the allowed value and is interposed between the connection to the cylinder and the exhaust connection, via a discharge chamber defined between the shutter and the valve body.

[0021] In one embodiment, the shutter allows the discharge of oil in the above chamber by means of a longitudinal portion of a channel inside the shutter, the channel having such a length as to extend up to reaching the discharge connection; then, through a calibrated hole transversely placed and which acts as a bottleneck, a connection is created between the shutter channel and the discharge connection.

[0022] In one embodiment, the shutter allows the discharge of the oil into the discharge chamber by means of one or more lowerings defining respective longitudinal passages on the end shank of the shutter; from the discharge chamber, the oil in over-pressure draws through said openings and goes to discharge.

[0023] The object of the present invention is also a tipper motor vehicle, of the type comprising at least

a. one hydraulic cylinder adapted to actuate a tipper body,

b. a lifting valve flange-associable to said cylinder with associated limiting device,

c. a fixed abutment element adapted to interact with said valve, in particular a pneumatic drive limiter device thereof.

BRIEF DESCRIPTION OF THE FIGURES

[0024] This and other features will become more apparent from the following description of some of the configurations, illustrated purely by way of example in the accompanying drawings.

• Figure 1 and 1A: show the valve for a hydraulic cylinder object of the invention, with limiting device, according to two respective perspective positions,
• Figure 2: shows the valve in figure 1 according to a lateral view;
• Figure 3: shows section B-B of the relief valve,
• Figure 4: shows the valve according to a lateral view, opposite to that in figure 2, partially sectional,
• Figure 5: shows the median section A-A of the lifting valve,
• Figure 6: shows the valve seen from the top,
• Figure 7: shows the sectional valve with connecting passages with the relief valve, chamber, shutter and discharge, according to a first embodiment,
• Figure 8: shows the sectional valve with connecting passages with the relief valve, chamber, shutter and discharge, according to a second embodiment,
• Figure 9 and 9A: shows the end of the shutter of the valve in figure 8 with relative detail.
• Figure 10 and 11: shows the cylinder group, with valve applied and fixed abutment adapted to control the limiting device of the shutter pneumatic drive.
• Figure 12: shows a variant of the discharge of the pneumatic drive unit by finger lever of the limiting device associated with the valve.

DESCRIPTION OF THE INVENTION

[0025] With reference first to the figures 10 and 11, a hydraulic cylinder group 10 is shown, adapted to be mounted on a commercial vehicle (not shown), such as a tipper, and used for lifting said body.

[0026] As known, the oil pumped into the body of the cylinder causes the displacement and distancing of the piston and, consequently, such a cylinder group exerts a force in extension, upwards, so as to lift the tipper. In contrast, the oil drained from the cylinder body by gravity causes the piston to retract into position, thus recalling the cylinder and consequently lowering the tipper.

[0027] When lifting, while the cylinder extends and lifts the tipper attached thereto at one end, at the same time it carries out a rotation, being hinged with pins or longitudinal members or supports at the opposite end.

[0028] A lifting valve 1 is also provided on the outer jacket 20 of the cylinder, implemented according to the invention.

[0029] The valve is constrainable to jacket 20 of cylinder 10 by means of a flange 2 or equivalent system. As will be better illustrated herein, the valve is adapted to control the oil flow to the hydraulic cylinder.

[0030] Preferably, the hydraulic cylinder is provided with a single hydraulic connection on one side only.

[0031] Referring now to figure 5, valve 1 of the present invention will now be outlined in detail.

[0032] Valve 1 comprises a valve body 3 comprising an inner wall 30 that defines a shutter cavity 4, which in turn is adapted to receive a shutter 5 sliding lengthwise in said chamber so as to make a seal against the wall of said chamber.

[0033] The lifting valve 1 further comprises:

• a first connection 6 intended for the connection of a pump of the hydraulic drive circuit of the hydraulic cylinder,
• a second connection 7 for the hydraulic connection with the hydraulic cylinder 10,
• a third connection 8 for the connection to an oil discharge tank.

[0034] Preferably, the shutter cavity 4 and shutter 5 have a longitudinal arrangement; in this way, by sliding to the right or the left (with respect to a neutral position, shown in the figure), the shutter connects a channel, so as to establish according to the cases:

• the connection for the tank,
• the connection for the pump,
• the connection for the cylinder.

[0035] As will be explained in greater detail below, when shutter 5 is slid to the right, the first connection 6 is put in communication with the second connection 7, thus putting the pump in communication with the hydraulic cylinder, thereby providing oil to the same, causing the extension thereof. In this configuration, a shoulder made on shutter 5 closes the passage to the third connection 8 to discharge. In contrast, when it is slid to the left, the first connection 6 is put in communication with the third connection 8, thus setting the pump to discharge.

[0036] The action described above is managed by a pneumatic drive unit 9, placed at one end 31 of the valve body 3, so that the pneumatic drive unit 9 is in direct connection with a portion of end 31 of said shutter 5. In a preferred embodiment, in order to achieve such a direct connection, the pneumatic drive unit 9 comprises a tubular jacket 90 that mates with the end portion 31 of the valve body 3 which, to this end, is open. It will be clear that the tubular jacket 90 may also be formed as a single body with the valve body 3.

[0037] The drive unit 9 is advantageously configured to axially move shutter 5 in the shutter cavity 4 of the valve and define at least three different positions, of which:

• a neutral position,
• a lifting position, namely i.e. of tipping of the body,
• a lowering position.

[0038] In the lifting position, shutter 5 is moved to the right while in the lowering position, it is moved to the left, as shown above.

[0039] Preferably, the shutter is maintained in a neutral position by a spring M1 against an abutment defined in wall 30.

[0040] According to a preferred embodiment, shutter 5 is substantially a stem, worked axially to define recesses and ribs such as to interfere with respective seats into chamber 4 of the valve body 4 and make the connections shown above.

[0041] More precisely, in the neutral position, the shutter puts the oil coming from the pump in communication with connection 8 of the tank, closing at the same time connection 7 to the cylinder. In this configuration, cylinder 10 cannot move.

[0042] Moreover, in lifting position, the shutter is moved, in the present case to the right, so that the pump is in communication with the connection of the cylinder. According to a preferred embodiment, this configuration is implemented by the drive unit 9 that, to that end, accommodates one an end of shutter 5 on which a plate 91 is supported that defines a first chamber C1 and a second chamber C2 in the tubular jacket 90.

[0043] Following the supply of compressed air in the first chamber C1 via a corresponding inlet S1, a force is induced to the right (with reference to the figures) that opens the pump-cylinder connection and closes the pump and discharge connection. In this way, the oil pressure actuates the cylinder in extension and lifts the body.

[0044] As discussed above, in the lowering position shutter 5 is displaced so that the pump and the cylinder are in communication with the discharge and, therefore, the oil present in the pump is discharged. This configuration is implemented by the drive unit 9 following the supply of compressed air in the second chamber C2, through a corresponding inlet S2, thus inducing a shutter displacement force to the left (with reference to the figures) so as to open both the pump-discharge connection and the connection to the cylinder which is thus also connected to discharge. In this way, the cylinder is recalled by gravity and the body lowers.

[0045] The lifting valve 1 of the present invention further comprises a limiting device 15 of the pneumatic drive.

[0046] Again with reference to figure 5, device 15 is connected to the pneumatic drive unit and is thus also integral with body 3. Preferably, device 15 is connected to one end of the drive unit 9, opposite to the one connected to body 3. More generally, device 15 may be directly connected to body 3, in particular when the drive unit is formed as single body with the valve body 3. Therefore, according to one aspect of the invention, the limiting device 15 defines a closing wall of the end of the drive unit 9 and thus of the valve body 9 and then 3, according to details that will be explained in more detail below.

[0047] According to an embodiment, the limiting device 15 can be activated when the drive unit 9 is in the lifting position.

[0048] If activated, the limiting device 15 is configured to:

• put chamber C1 to discharge and at the same time close the air inlet from S1, thus interrupting the pneumatic supply to the shutter.

[0049] As can be seen in figure 5, following the interruption of the pneumatic supply to shutter 5, spring M1 recalls it to the neutral position.

[0050] Noting the arrangement of the connections in said neutral position, it follows that once the limiting device has been activated and the first chamber C1 has been set to discharge, the cylinder stroke remains fixed since shutter 5 returns to the center and puts the pump in communication with the discharge and isolates the cylinder both with the discharge and with the pump.

[0051] In fact, the situation is to stop the stroke and maintain the position of the cylinder.

[0052] Due to the presence of the limiting device 15, it is possible to block the cylinder stroke before reaching the maximum angle thereof.

[0053] In other words, the activation of the limiting device 15 is controlled before reaching the maximum excursion of the cylinder.

[0054] According to a preferred aspect, the activation of the limiting device 15 occurs through contact with one or more fixed abutment elements 17, shown in figure 10 and 11. In this way, during the actuation and simultaneous rotation of the cylinder, the abutment means interfere with the movement of the limiting device.

[0055] It should be noted that in the typical solutions, the cylinder is hinged at one end to the vehicle's chassis and at the other to the body. The lifting movement of the body is therefore associated with a rotation of cylinder 20 itself. Since, as noted above, the lifting valve 1 comprising the valve body 3 and the limiting device 15 integral thereto, is fixed to jacket 20 of the cylinder and is therefore also moved during the body lifting.

[0056] Therefore, the tipper motor vehicle is also provided, in addition to a hydraulic cylinder adapted to actuate a tipper body, with a lifting valve, both associated with the cylinder group 10 and a fixed abutment element adapted to interact with the valve, in particular with the limiting device 15 of the pneumatic drive.

[0057] Returning to the description of the features of the lifting valve, it is noted that in a preferred embodiment, the limiting device 15 comprises at least one actuating element 18, free to slide linearly with respect to an axis AA defined by a respective seat formed by an auxiliary cavity 14.

[0058] The limiting device also comprises at least a first spring M3, or other elastic device, opposing the inward sliding motion of the actuating element 18, and a slider or drawer 19.

[0059] In the embodiment shown, the actuating element 18, the first spring M3 and slider or drawer 19 are arranged axially aligned along axis AA in the same cavity 14.

[0060] According to another aspect of the invention, device 15 further comprises a second spring M2, or other elastic device, interposed between the actuating element 18 and an abutment surface of slider 19. Spring M3 is arranged on the opposite side to spring M2 and acts on the opposite side of slider 19 so as to recall it in position when the abutment element 17 does not act on the actuating element 18.

[0061] The purpose of the second spring M2 is to allow an extra stroke of the cylinder and prevent inertial oscillations thereof.

[0062] In a preferred embodiment, a channel 13 is provided, configured to connect place inlet S1 in communication with chamber C1 of the pneumatic drive unit 9. Through channel 13 it is possible to send the air under pressure from inlet S1 to chamber C1, resulting in the displacement of the shutter to the tipping position.

[0063] More specifically, in non-operational configuration of the limiting device, slider 19 through springs M2, M3 is positioned so as to leave the channel open and thus the connection between chamber C1 of the drive unit and the air inlet S1. To this end, slider 19 advantageously defines a connecting portion 25 comprised between two sealing elements 26 of slider 19 on the auxiliary cavity 14.

[0064] When springs M2 and M3 maintain slider 19 in a balanced position, channel 13 and the air inlet S1 both open within the auxiliary cavity at portion 25, thereby placing the channel 13 in communication with the air inlet S1, as can be seen in figures 4 and 5.

[0065] When the abutment means interfere with the actuating element, the latter by pushing spring M2, moves slider 19 to a position in which it closes inlet S1 and the air under pressure into chamber C1 escapes, for example, through a conduit 12 (axial in the example) inside the actuating element 18 and in communication with the external environment. Said conduit 12 may also be arranged differently, as shown in figure 12.

[0066] For example, by means of one or more transverse passages 12A made at a collar 27 closing the auxiliary cavity 14 and retaining the actuating element 18, the air under pressure can be set to discharge.

[0067] According to an exemplary embodiment, the actuating element 18 and slider 19 act on the perpendicular or more generally, transverse axis AA, or with respect to axis BB of shutter 5.

[0068] However, according to a further embodiment not shown, also movements in the same direction of movement of the shutter can be contemplated, in this case changing the arrangement of the lifting valve and the shape of the abutments.

[0069] The lifting valve 1 further comprises a relief valve 16, better shown in figures 6 to 8.

[0070] As shown in the figure, it is placed preferably longitudinally off axis and in hydraulic connection with the cylinder connection. In a preferred embodiment, the valve has an operating axis parallel to that of shutter 5.

[0071] The relief valve is configured to intervene when the pressure in the cylinder group exceeds the allowed value.

[0072] In the preferred embodiment, the relief valve is interposed between the cylinder connection of group 10 and the discharge connection, passing through a discharge chamber C4 defined between the shutter and the valve body. Preferably, chamber C4 is arranged axially opposite the drive unit 9, to the advantage of the compactness of the structure.

[0073] Specifically, the relief valve is calibrated to open its own shutter when the pressure in the cylinder reaches and exceeds the maximum sealing pressure, Pmax.

[0074] Once the shutter of the relief valve is open, the oil reaches the discharge chamber C4 through a calibrated passage. At this point, the shutter allows the discharge of oil through the discharge chamber C4.

[0075] In a first preferred embodiment shown in figure 8 and 9, the discharge of the oil into chamber C4 is allowed by means of one or more lowerings 23 defining respective passages on the end shank 24 of shutter 5; from the discharge chamber C4, the oil in over-pressure draws through the openings defined by lowerings 23 and goes to discharge.

[0076] The presence of the above lowerings implies an additional advantage, namely to have the portion corresponding to shutter 5 always clean, i.e. with a self-cleaning action due precisely to the movement imposed by shutter 5 in the operation thereof.

[0077] A second embodiment is the one shown in figure 7, which provides for a longitudinal portion of a blind channel 21 formed within and axially to shutter 5; said channel 21 having such a length as to extend up to reaching the discharge zone; then, through a second calibrated hole 22 arranged transversely (acting as a bottleneck), a connection is created between the shutter channel and the discharge channel.

[0078] In general, shutter 5 allows discharging the oil in chamber C4 by combining a channel 21 and a calibrated hole 22, both inside the shutter.

[0079] In both embodiments, shutter 5 of valve 1 is returned to the center so that the cylinder can be put to safety conditions; this occurs since the discharge chamber C4 is under pressure, due to the presence of the calibrated passage defined by the calibrated holes or by the lowerings.

Claims

1. Valve (1) for a hydraulic cylinder group (10) adapted to control the oil flow to a cylinder of said hydraulic cylinder group (10), the cylinder being provided with a single hydraulic connection on one side only, the valve (1) comprising:

a. a body (3) adapted to enclose a wall that defines a shutter cavity (4),

b. a shutter (5) sliding in said shutter cavity (4) so as to provide a seal against the wall of said shutter cavity (4),

c. a first connection (6) for the connection to a pump adapted to provide an oil flow,

d. a second connection (7) for the connection to the cylinder of the hydraulic cylinder group (10),

e. a third connection (8) for the connection to a discharge tank,

f. a pneumatic drive unit (9) in which a first chamber (C1) is defined to axially move the shutter (5) in the shutter cavity (4) of the valve (1) by a compressed air flow and define at least three different positions including a neutral position, a lifting position, and a lowered position,

g. a limiting device (15) that can be activated when the drive unit is in lifting position and being movable between a non-operating position in which the passage of compressed air from an inlet (S1) to the first chamber (C1) is allowed, and an operating position in which the first chamber (C1) of the drive unit is set to discharge and the pneumatic supply to the valve shutter is interrupted,

characterized in that said limiting device (15) is rigidly connected to said pneumatic drive unit (9) at one end in which said first chamber (C1) is defined, and in that said limiting device (15) includes a slider (19) and an actuating element (18), said slider (19) being movable by abutment of said actuating element (18) against an actuating element (17) fixable to a support structure of the hydraulic cylinder group (10) in order to bring the limiting device (15) selectively in the non-operating position or in the operating position.

2. Valve according to claim 1, wherein the limiting device (15) comprises an auxiliary cavity (14) that defines a seat within which the slider (19) can slide linearly.

3. Valve according to claim 2, wherein the slider (19) is slidable along an axis (AA) substantially perpendicular to a sliding axis of the shutter (5).

4. Valve according to claim 2 or 3, wherein the slider (19) defines a connecting portion (25) comprised between two sealing elements (26) of the slider (19) on the cavity (14); a channel (13) and the inlet (S1) open within the auxiliary cavity (14) at the connecting portion (25) when the slider (19) is in a balance position in such a way as to allow the flow of an air flow to the first chamber (C1).

5. Valve according to one of the preceding claims, wherein the limiting device (15) is connected to one end of the drive unit (9) and defines a closing wall of one end of the drive unit (9).

6. Valve according to claim 5, wherein said first chamber (C1) is defined in a tubular jacket (90), said tubular jacket having an open end, closed by the limiting device (15).

7. Valve according to claim 6, wherein said tubular jacket (90) couples with an end portion (31) of the valve body (3).

8. Valve according to one of the preceding claims, wherein the limiting device (15) comprises at least one elastic device (M2, M3) adapted to keep the slider (19) in the balance position in the absence of stress on the actuating element (18).

9. Valve according to claim 8, wherein said elastic device comprises at least a first return spring (M3) maintaining the slider (19) in the balance position; the actuating element (18), the first spring (M3) and the slider (19) being arranged axially aligned.

10. Valve according to claim 9, wherein said elastic device comprises a second spring (M2) interposed between the actuating element (18) and the slider (19); said second spring (M2) being adapted to allow an extra stroke of the cylinder.

11. Valve according to one of the preceding claims, wherein one or more passages (12, 12A) are defined for discharging and thus releasing said air under pressure from the first chamber (C1); said one or more passages (12, 12A) being formed within the actuating element (18) or at a collar (27) which closes the cavity (14) and retains the actuating element (18).

12. Valve according to one of the preceding claims, comprising a relief valve (16) in hydraulic connection with the second connection (7) for the cylinder, said relief valve (16) is configured to intervene when the pressure in the cylinder group exceeds the allowed value.

13. Valve according to claim 12, wherein said relief valve (16) is interposed between the second connection (7) to the cylinder and the third connection (8) to the discharge tank, through a discharge nozzle (C4); the shutter (5) comprises one or more lowerings (23) defining respective passages on the end shank (24) of the shutter (5), through which it discharges the oil into the discharge chamber (C4), said shank (24) being placed at the end opposite that of the first chamber (C1).

14. Hydraulic cylinder group (10) comprising a hydraulic cylinder which includes a jacket (20) and a valve (1) according to one of the preceding claims, wherein said body (3) of the valve (5) is rigidly fixed to the jacket (20) of the cylinder so that the actuating element (18) of the limiting device (15) is protruding from the jacket (20).

15. Hydraulic cylinder group (10) according to claim 14, wherein the shutter (3) of the valve (1) is slidable along a direction transverse to the axis of the cylinder.

16. Hydraulic cylinder group (10) according to claim 14 or 15, comprising a support structure of a rotation pin of the hydraulic cylinder and an abutment element integrally placed on said support structure.

17. Motor vehicle, of the type comprising at least

a. a tipper body,

b. a hydraulic cylinder group (10) according to one of claims 14 to 16, adapted to actuate the tipper body,

c. an abutment element (17) rigidly fixed to a frame of the motor vehicle and adapted to interact with the actuating element (18) of the valve (1).

18. Motor vehicle according to claim 17, wherein the abutment (17) is placed in such a way as to interfere with the movement of the limiting device (15) during the rotation of the cylinder of the hydraulic cylinder group (10).

Ansprüche

1. Ventil (1) für eine Gruppe von Hydraulikzylindern (10), die dazu ausgelegt sind, den Ölstrom zu einem Zylinder dieser Gruppe von Hydraulikzylindern (10) zu steuern, wobei der Zylinder nur auf einer Seite mit einem einzigen Hydraulikanschluss versehen ist, wobei das Ventil (1) umfasst:

a. einen Körper (3), der zum Umschließen von einer Wand geeignet ist, die einen Hohlraum (4) eines Verschlusses definiert,

b. einen Verschluss (5), der in den Hohlraum des Verschlusses (4) gleitet, um eine Abdichtung gegen die Wand des Hohlraums des Verschlusses (4) herzustellen,

c. einen ersten Anschluss (6) zum Anschluss an eine Pumpe, die zum Fördern eines Ölstroms geeignet ist,

d. einen zweiten Anschluss (7) zum Verbinden der Hydraulikzylindergruppe (10) mit dem Zylinder,

e. einen dritten Anschluss (8) zum Anschluss an einen Abfalltank,

f. eine pneumatische Steuereinheit (9), in der eine erste Kammer (C1) definiert ist, um den Verschluss (5) mittels eines Druckluftstroms axial in den Hohlraum (4) des Verschlusses des Ventils (1) zu bewegen und um mindestens drei verschiedene Positionen, einschließlich einer neutralen Position, einer angehobenen Position und einer abgesenkten Position, zu definieren,

g. eine Begrenzungsvorrichtung (15), die aktiviert werden kann, wenn sich die Antriebseinheit in einer angehobenen Position befindet und zwischen einer nicht betriebsbereiten Position bewegt werden kann, in der Druckluft von einem Einlass (S1) zur ersten Kammer (C1) zulässig ist, und eine Betriebsposition, in der die erste Kammer (C1) der Antriebseinheit auf Entladung eingestellt und die pneumatische Versorgung des Ventilverschlusses unterbrochen wird,

dadurch gekennzeichnet, dass die Begrenzungsvorrichtung (15) starr mit der pneumatischen Betätigungseinheit (9) verbunden ist, an einem Ende, in dem die erste Kammer (C1) definiert ist, und dass die Begrenzungsvorrichtung (15) einen Schieber (19) und ein Betätigungselement (18) umfasst, wobei der Schieber (19) beweglich ist, indem er das Betätigungselement (18) gegen ein Betätigungselement (17) stößt, das an einer Stützstruktur der Gruppe von Hydraulikzylindern (10) befestigt werden kann, um die Begrenzungsvorrichtung (15) selektiv in die nicht betriebsbereite Position oder in die Betriebsposition zu bringen.

2. Ventil nach Anspruch 1, wobei die Begrenzungsvorrichtung (15) einen Hilfshohlraum (14) umfasst, der einen Sitz definiert, in dem der Schieber (19) linear gleiten kann.

3. Ventil nach Anspruch 2, wobei der Schieber (19) entlang einer Achse (AA) gleitet, die im Wesentlichen senkrecht zu einer Gleitachse des Verschlusses (5) ist.

4. Ventil nach Anspruch 2 oder 3, wobei der Schieber (19) einen Verbindungsteil (25) definiert, der zwischen zwei Dichtungselementen (26) des Schiebers (19) auf dem Hohlraum (14) angeordnet ist; ein Kanal (13) und der Einlass (S1) sind innerhalb des Hilfshohlraums (14) am Verbindungsteil (25) offen, wenn sich der Schieber (19) im Gleichgewicht befindet, um den Durchgang einer Luftströmung in der ersten Kammer (C1) zu ermöglichen.

5. Ventil nach einem der vorhergehenden Ansprüche, wobei die Begrenzungsvorrichtung (15) mit einem Ende der Antriebseinheit (9) verbunden ist und eine Schließwand eines Endes der Antriebseinheit (9) definiert.

6. Ventil nach Anspruch 5, wobei die erste Kammer (C1) in einem rohrförmigen Gehäuse (90) definiert ist, wobei das rohrförmige Gehäuse ein offenes Ende aufweist, das durch die Begrenzungsvorrichtung (15) geschlossen ist.

7. Ventil nach Anspruch 6, wobei das rohrförmige Gehäuse (90) mit einem Endbereich (31) des Ventilkörpers (3) verbunden ist.

8. Ventil nach einem der vorhergehenden Ansprüche, wobei die Begrenzungsvorrichtung (15) mindestens eine elastische Vorrichtung (M2, M3) umfasst, die in der Lage ist, den Schieber (19) in der Gleichgewichtsposition zu halten, ohne dass eine Belastung für die Betätigungselement (18) entsteht.

9. Ventil nach Anspruch 8, wobei die elastische Vorrichtung mindestens eine erste Rückstellfeder (M3) umfasst, die den Schieber (19) in der Gleichgewichtsposition hält; wobei das Betätigungselement (18), die erste Feder (M3) und der Schieber (19) axial ausgerichtet sind.

10. Ventil nach Anspruch 9, wobei die elastische Vorrichtung eine zweite Feder (M2) umfasst, die zwischen dem Betätigungselement (18) und dem Schieber (19) angeordnet ist; wobei die zweite Feder (M2) angepasst ist, um einen weiteren Hub des Zylinders zu ermöglichen.

11. Ventil nach einem der vorhergehenden Ansprüche, in dem ein oder mehrere Durchgänge (12, 12A) definiert sind, um die Druckluft aus der ersten Kammer (C1) zu entladen und dann abzulassen; wobei ein oder mehrere Durchgänge (12, 12A) innerhalb des Betätigungselements (18) oder in der Nähe eines Kragens (27) ausgebildet sind, der den Hohlraum (14) schließt und das Betätigungselement (18) hält.

12. Ventil nach einem der vorhergehenden Ansprüche, umfassend ein Auslassventil (16) in hydraulischer Verbindung mit dem zweiten Anschluss (7) für den Zylinder, wobei das Auslassventil (16) derart konfiguriert ist, dass es eingreift, wenn der Druck in der Zylindergruppe höher als der zulässige Wert ist.

13. Ventil nach Anspruch 12, wobei das Auslassventil (16) zwischen dem zweiten Anschluss (7) und dem Zylinder und dem dritten Anschluss (8) und dem Ablauf tank durch eine Auslassdüse (C4) angeordnet ist; der Verschluss (5) umfasst einen oder mehrere abgesenkte Teile (23), die entsprechende Durchgänge am Endschaft (24) des Verschlusses (5) definieren, durch die er das Öl in die Auslasskammer (C4) abgibt; wobei der Schaft (24) in Bezug auf den der ersten Kammer (C1) am entgegengesetzten Ende angeordnet ist.

14. Hydraulikzylinderanordnung (10), umfassend einen Hydraulikzylinder, der ein Gehäuse (20) und ein Ventil (1) gemäß einem der vorhergehenden Ansprüche umfasst, wobei der Körper (3) des Ventils (5) derart starr an dem Gehäuse (20) des Zylinders befestigt ist, dass das Betätigungselement (18) der Begrenzungsvorrichtung (15) aus dem Gehäuse (20) herausragt.

15. Hydraulikzylinderanordnung (10) nach Anspruch 14, wobei der Verschluss (3) des Ventils (1) entlang einer Richtung quer zur Achse des Zylinders gleiten kann.

16. Hydraulikzylinderanordnung (10) nach Anspruch 14 oder 15, umfassend eine Stützstruktur für einen Drehstift des Hydraulikzylinders und ein Widerlagerelement, das integral an der Stützstruktur angeordnet ist.

17. Kraftfahrzeug des Typs, der mindestens umfasst

a. einen umkippender Körper,

b. eine Hydraulikzylinderanordnung (10) nach einem der Ansprüche 14 bis 16, die zum Betätigen des umkippenden Körpers geeignet ist,

c. ein Widerlagerelement (17), das starr an einem Rahmen des Kraftfahrzeugs befestigt und angepasst ist, um mit dem Betätigungselement (18) des Ventils (1) in Wechselwirkung zu treten.

18. Kraftfahrzeug nach Anspruch 17, wobei das Widerlager (17) derart angeordnet ist, dass es die Bewegung der Begrenzungsvorrichtung (15) während der Drehung des Zylinders der Hydraulikzylinderanordnung (10) stört.

Revendications

1. Soupape (1) pour un groupe de cylindres hydrauliques (10) adaptée pour commander un débit d'huile vers un cylindre dudit groupe de cylindres hydrauliques (10), le cylindre étant pourvu d'une seule connexion hydraulique d'un seul côté, la soupape (1) comprenant:

a. un corps (3) adapté pour enfermer une paroi qui définit une cavité (4) d'un obturateur,

b. un obturateur (5) coulissant dans ladite cavité (4) de l'obturateur, de manière à réaliser un joint contre la paroi de ladite cavité (4) de l'obturateur,

c. une première connexion (6) pour la connexion à une pompe adaptée pour alimenter un débit d'huile,

d. une deuxième connexion (7) pour la connexion au cylindre du groupe de cylindres hydrauliques (10),

e. une troisième connexion (8) pour la connexion à un réservoir de décharge,

f. une unité de commande pneumatique (9) dans laquelle une première chambre (C1) est définie pour déplacer axialement l'obturateur (5) dans la cavité (4) de l'obturateur de la soupape (1) au moyen d'un flux d'air comprimé et pour définir au moins trois positions différentes comprenant une position neutre, une position relevée et une position abaissée,

g. un dispositif de limitation (15) qui peut être activé lorsque l'unité de commande se trouve dans une position relevée et peut être déplacée entre une position inopérante dans laquelle le passage de l'air comprimé d'une entrée (S1) à la première chambre (C1) est autorisée, et une position opérante dans laquelle la première chambre (C1) de l'unité de commande est réglée pour le décharge et l'alimentation pneumatique à l'obturateur de la soupape est interrompue,

caractérisée en ce que ledit dispositif de limitation (15) est relié rigidement à ladite unité de commande pneumatique (9), à une extrémité dans laquelle ladite première chambre (C1) est définie, et que ledit dispositif de limitation (15) comprend un curseur (19) et un élément d'actionnement (18), ledit curseur (19) étant mobile en butant ledit élément d'actionnement (18) contre un élément d'actionnement (17) qui peut être fixé à une structure de support du groupe de cylindres hydrauliques (10), pour amener sélectivement le dispositif de limitation (15) en position de repos ou en position de fonctionnement.

2. Soupape selon la revendication 1, dans laquelle le dispositif de limitation (15) comprend une cavité auxiliaire (14) qui définit un siège à l'intérieur duquel le curseur (19) peut coulisser linéairement.

3. Soupape selon la revendication 2, dans laquelle le curseur (19) peut coulisser le long d'un axe (AA) sensiblement perpendiculaire à un axe de coulissement de l'obturateur (5).

4. Soupape selon la revendication 2 ou 3, dans laquelle le curseur (19) définit une partie de connexion (25) comprise entre deux éléments d'étanchéité (26) du curseur (19) sur la cavité (14); un canal (13) et l'entrée (S1) étant ouverts à l'intérieur de la cavité auxiliaire (14) sur la pièce de raccordement (25) lorsque le curseur (19) se trouve dans une position d'équilibre de manière à permettre le passage d'un flux d'air dans la première chambre (C1).

5. Soupape selon l'une des revendications précédentes, dans laquelle le dispositif de limitation (15) est connecté à une extrémité de l'unité de commande (9) et définit une paroi de fermeture d'une extrémité de l'unité de commande (9).

6. Soupape selon la revendication 5, dans laquelle ladite première chambre (C1) est définie dans un boîtier tubulaire (90), ledit boîtier tubulaire ayant une extrémité ouverte, fermée par le dispositif de limitation (15) .

7. Soupape selon la revendication 6, dans laquelle ledit boîtier tubulaire (90) est couplé à une partie d'extrémité (31) du corps (3) de la soupape.

8. Soupape selon l'une des revendications précédentes, dans laquelle le dispositif de limitation (15) comprend au moins un dispositif élastique (M2, M3), apte à maintenir le curseur (19) dans la position d'équilibre en l'absence de contrainte sur l'élément d'actionnement (18).

9. Soupape selon la revendication 8, dans laquelle ledit dispositif élastique comprend au moins un premier ressort de rappel (M3), qui maintient le curseur (19) dans le position d'équilibre; l'élément d'actionnement (18), le premier ressort (M3) et le curseur (19) étant disposés axialement alignés.

10. Soupape selon la revendication 9, dans laquelle ledit dispositif élastique comprend un deuxième ressort (M2) interposé entre l'élément d'actionnement (18) et le curseur (19); ledit deuxième ressort (M2) étant adapté pour permettre une course supplémentaire du cylindre.

11. Soupape selon l'une des revendications précédentes, dans laquelle un ou plusieurs passages (12, 12A) sont définis pour décharger et donc libérer ledit air sous pression de la première chambre (C1); lesdits un ou plusieurs passages (12, 12A) étant formés à l'intérieur de l'élément d'actionnement (18) ou à proximité d'un collier (27) qui ferme la cavité (14) et retient l'élément d'actionnement (18).

12. Soupape selon l'une des revendications précédentes, comprenant une soupape de d'échappement (16) en connexion hydraulique avec la deuxième connexion (7) pour le cylindre, ladite soupape d'échappement (16) étant configurée pour intervenir lorsque la pression dans le groupe de cylindres est supérieure à la valeur autorisée.

13. Soupape selon la revendication 12, dans laquelle ladite soupape de décharge (16) est interposée entre la deuxième connexion (7) et le cylindre et la troisième connexion (8) et le réservoir de décharge, à travers une buse de décharge (C4); l'obturateur (5) comprend une ou plusieurs parties abaissées (23) qui définissent des passages respectifs sur la tige d'extrémité (24) de l'obturateur (5), à travers lesquels il décharge l'huile dans la chambre de décharge (C4), ladite tige (24) étant disposée à l'extrémité opposée par rapport à celle de la première chambre (C1).

14. Unité de cylindre hydraulique (10) comprenant un cylindre hydraulique qui comprend un boîtier (20) et une soupape (1) selon l'une des revendications précédentes, dans laquelle ledit corps (3) de la soupape (5) est fixé rigidement au boîtier (20) du cylindre, de sorte que l'élément d'actionnement (18) du dispositif de limitation (15) fait saillie depuis le boîtier (20).

15. Ensemble de cylindre hydraulique (10) selon la revendication 14, dans lequel l'obturateur (3) de la soupape (1) peut coulisser le long d'une direction transversale à l'axe du cylindre.

16. Ensemble de cylindres hydrauliques (10) selon la revendication 14 ou 15, comprenant une structure de support pour une broche rotative du cylindre hydraulique et un élément de butée disposé intégralement sur ladite structure de support.

17. Véhicule automobile, du type comportant au moins

a. un corps basculant,

b. un ensemble de cylindres hydrauliques (10) selon l'une des revendications 14 à 16, adapté pour actionner le corps basculant,

c. un élément de butée (17) fixé rigidement à un châssis du véhicule automobile et apte à coopérer avec l'élément d'actionnement (18) de la soupape (1) .

18. Véhicule automobile selon la revendication 17, dans lequel la butée (17) est placée de manière à gêner le mouvement du dispositif de limitation (15) lors de la rotation du cylindre de l'ensemble de cylindres hydrauliques (10).

Drawing