VEHICLE'S TIPPER BODY

DESCRIPTION

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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

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

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.

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

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

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.

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.

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.

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

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

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.

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.

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.

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

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.

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

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

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.

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.

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.

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.

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.

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.

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.

Preferably, the shutter is maintained in a neutral position by a spring Ml against an abutment defined in wall 30.

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.

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.

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 CI and a second chamber C2 in the tubular jacket 90.

Following the supply of compressed air in the first chamber CI via a corresponding inlet SI, 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.

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.

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

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. according to an embodiment, the limiting device 15 can be activated when the drive unit 9 is in the tilting position.

If activated, the limiting device 15 is configured to:

- put chamber CI to discharge and at the same time close the air inlet from SI, thus interrupting the pneumatic supply to the shutter.

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

Noting the arrangement of the connections in said neutral position, it follows that once the limiting device has been activated and the first chamber CI 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.

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

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

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

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.

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.

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.

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.

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.

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.

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.

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

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

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 CI of the drive unit and the air inlet SI . 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.

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

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 SI and the air under pressure into chamber CI 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.

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.

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.

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.

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

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.

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

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.

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.

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.

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.

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.

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.

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.

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.