Patent Description:
The known painting systems usually comprise at least one painting gun configured to spray a painting fluid on an object to be painted.

This gun, airbrush, thus comprises an opening that enables this painting fluid, usually pressurised, to flow out in the direction of the object to be painted.

In the prior art, the adjustment of the flow of fluid in painting circuits where airbrush guns are used may occur in the following ways:.

Clearly, a centralised control where the adjustment of the painting fluid flow is performed upstream of the gun feeding tubes is imprecise, since the same fluid flow is provided to all the guns because every gun would be fed with a flow designed to meet the needs of that with the greatest need for fluid. A dedicated adjustment for each gun, at the hydraulic level, would, instead, by extremely complex, bulky, and costly.

A manual adjustment, on the other hand, substantially impacts the maintenance time for the painting systems, having to manually adjust each gun in order to modify the amount of paint to deliver.

Finally, the use of intermediate adjustment devices to be inserted in line on the painting circuit does not enable a precise adjustment when small amounts of product are required to be delivered. They increase the time needed for managing the system since more time is needed for maintenance and they may be subject to blockages due to the narrow internal passages where the paint flows.

Example of known devices in the art are disclosed in ITTO980443 A1, <CIT>, <CIT>, <CIT> or <CIT>.

There is, thus, a need to provide painting guns that may be adjusted in an automatic, compact, precise, and economical way.

There is, also, the need to limit the maintenance times and without needing to add other devices that act on the paint feeding circuit.

The purpose of this invention is to meet the requirements mentioned above.

The above-mentioned purpose is achieved with a painting gun and a painting system as claimed in the attached independent claims.

Additional, preferred embodiments of the invention are constructed according to the dependent claims or those connected to the independent claims mentioned above.

To better understand this invention a preferred embodiment is described below, by way of non-limiting example and with reference to the attached drawings, in which:.

In <FIG>, a portion of a painting system <NUM> is illustrated comprising at least one painting assembly <NUM> each equipped with a painting gun <NUM>. In the figure illustrated, there is a single painting assembly <NUM>, for simplicity. In particular, the painting gun <NUM> extends along a longitudinal axis A and is supported by a support <NUM> that can be fixed to a body (not illustrated) fixed to the painting system <NUM>.

Advantageously, the support <NUM> comprises a fixing portion 4a configured to fix the support <NUM> to the body of the painting system <NUM>.

The support <NUM> defines, in addition, a first and a second lateral relief <NUM> extending longitudinally parallel to the axis A and overhanging the fixing portion 4a. The support <NUM> is preferably made of material that remains unaltered and stable over time, such as stainless steel.

The first and the second lateral relief <NUM> transversely delimit between them a seat designed to partially house the painting gun <NUM>.

The painting gun <NUM> defines a casing 3a, preferably cylindrical in shape and configured to delimit an internal space 3b designed to house a flow adjustment system <NUM> for the painting gun as described below.

As known, the flow adjustment system <NUM> comprises a rod 6a configured to open or close the free section of an opening <NUM>, preferably defined as a nozzle outlet section. The opening <NUM> is fluidically connected to a known source <NUM> of painting fluid.

In particular, the rod 6a is connected to adjustment means <NUM> configured to adjust the maximum vertical stroke position along the axis A of this rod 6a as described below.

As is known, the movement of the rod 6a along the axis A is actuated using a pneumatic system 6b. In particular, the pneumatic system 6b comprises a piston 6c actuated via the entry of air from the duct 6d' and returned to the neutral position, i.e., against the elastic means 6f closure when the air is made to flow from the duct 6d'.

The piston 6c is connected to a second piston <NUM> that is integral thereto and configured to enable the passage of compressed air coming from a duct 6d'' that may then flow towards the opening <NUM>. In particular, the air flows in ducts that are fluidically separate to the opening <NUM> and communicating with the outside via orifices 3b made around the opening <NUM>.

Since the components of the flow adjustment system <NUM> are known, they will not be described in any more detail for the sake of brevity.

The rod 6a is carried by the cylinder 6c and follows the movements thereof between a first end position, lower, wherein the opening <NUM> is closed by the rod 6a, and a second end position, higher and the maximum stroke of which is delimited by the adjustment means <NUM>, wherein, between the rod 6a and the opening <NUM>, a section for the passage of painting fluid coming from the source <NUM> is free.

These adjustment means <NUM> essentially comprise a wheel <NUM> configured to rotate about the axis A and actuator means <NUM> configured to adjust this rotation of the wheel <NUM>.

Advantageously, these actuator means <NUM> are pneumatic actuator means.

According to the advantageous embodiment described, the adjustment means <NUM> comprise first actuator means <NUM>' configured to enable the rotation of the wheel <NUM> clockwise around the axis A and according to actuator means <NUM>'' configured to enable the rotation of the wheel <NUM> anticlockwise around the axis A. Clearly, the actuator means <NUM>', <NUM>'' work alternatively, the one in relation to the other.

The clockwise or anticlockwise rotation of the wheel <NUM> enables, respectively, the reduction or increase of the second end portion, i.e., the upper stop of the rod 6a, thus changing the maximum passage section between rod 6a and opening <NUM>.

According to an embodiment illustrated in <FIG> and following, each of the actuator means <NUM> comprises a tip <NUM> housed freely in relation to the translation in a support element <NUM> and configured to cooperate in contact with respective seats <NUM> made on the wheel <NUM> to control the rotation thereof.

The seats <NUM> are preferably equally angularly spaced apart circumferentially so that between one seat <NUM> and the other, there is the same angular pitch. In the case described, there are twenty seats <NUM> equally spaced apart by <NUM>° around the axis A.

In particular, the support element <NUM> is configured to be fixed to the support <NUM> in such a position so as to be able to laterally wind, at least partially, the wheel <NUM> of the painting gun <NUM>. In particular, when fixed to the support <NUM>, the fixing element extends so that it overhangs the fixing portion 4a of the support <NUM>, preferably perpendicularly to it.

The support element <NUM> preferably comprises, thus, a fixing portion configured to fix the same to the support <NUM> and an end portion configured to wind, at least in part, the wheel <NUM> of the painting gun <NUM>.

This end portion preferably defines an arched portion facing the wheel <NUM> and, more preferably, concentric to it.

The support element <NUM> is, advantageously, hollow, i.e., it defines a through opening <NUM> configured to house, within, the tip <NUM> and to enable the translation thereof along an axis C, preferably parallel to the axes A and B.

In particular, the through opening <NUM> comprises a first portion <NUM>', an intermediate portion <NUM>'', and a second portion <NUM>‴, that are opposite along the axis C in relation to the first portion <NUM>'. Advantageously, all the portions <NUM>', <NUM>", and <NUM>‴ are advantageously axially symmetrical, preferably cylindrical, and the first portion <NUM>' has transverse dimensions in relation to the axis C that are greater compared to the intermediate portion <NUM>" that, in turn, has transverse dimensions in relation to the axis C that are greater compared to the second portion <NUM>‴. According to the embodiment illustrated, the diameter of the first portion <NUM>' is greater than the diameter of the intermediate portion <NUM>" that, in turn, is greater than the diameter of the second portion <NUM>‴.

The second portion <NUM>‴ is sized so that the tip <NUM> cooperates in contact with the internal walls radially delimiting the second portion <NUM>‴.

In particular, the tip <NUM> comprises a first end portion 12a configured to mechanically cooperate with the wheel <NUM> and partially slidable in the second portion <NUM>‴ of the opening <NUM> and a second end portion 12b, opposite the first end portion 12a, and configured to slide inside the first portion <NUM>' of the fluid-tight opening <NUM>. The first and the second end portions are connected to each other by means of an intermediate portion 12c.

The second end portion 12b basically defines a piston that thus divides the first portion <NUM>' in a first portion <NUM>' fluidically in contact with a pressurised fluid source F and a second portion <NUM>'b fluidically separated from the first portion <NUM>'a.

The pressurised fluid source F, not illustrated, is advantageously a pneumatic source configured to selectively provide a pressurised air flow F inside the second portion <NUM>'b so as to exert a force on the second end portion 12b, thus on the tip <NUM>.

The tip <NUM> is configured to be moved along the axis C between a first (rest) operating position (<FIG>) wherein the first end portion 12a does not cooperate with the wheel <NUM> and a second (actuation) operating position (<FIG>) wherein the first end portion 12a cooperates in contact with the wheel <NUM>.

In particular, the actuator means <NUM> comprise elastic means <NUM> configured to maintain the tip <NUM> in the first operating condition. These elastic means are preferably operationally placed between the second end portion 12b and the support element <NUM>', more preferably within the opening <NUM>.

According to the embodiment described, the elastic means <NUM> are housed inside the second and third portion <NUM>', <NUM>" of the opening <NUM>.

In particular, the elastic means <NUM> comprise a helical spring <NUM> housed around the intermediate portion 12c of the tip <NUM>, preferably coaxial to it, and comprising a first end in contact with the shoulder defined by the narrowing between the second and third portion <NUM>", <NUM>‴ of the opening <NUM> and a second end in contact with the second end portion 12b of the tip <NUM>.

The tip <NUM> advantageously comprises a pawl <NUM> movably carried by the first end portion 12a of the tip <NUM> and configured to cooperate in contact with the wheel <NUM>.

In particular, the pawl <NUM> is advantageously L-shaped, i.e., comprising a first arm <NUM>' and a second arm <NUM>" connected via a hinge connection <NUM> to the first end portion 12a of the tip <NUM>. Advantageously, the first and the second arm <NUM>', <NUM>'' consist of a single piece. The hinge <NUM> enables the rotation of the pawl <NUM> around an axis parallel to the axis A between a first and a second limit value.

In particular, the first arm <NUM>' is sized so as to cooperate with the seats <NUM> of the wheel <NUM> to control the movement of the latter when in one of the rotation limit conditions of the pawl <NUM>.

The actuator means <NUM> advantageously comprise thrust means <NUM> configured to exert a direct force against the tip <NUM> during its stroke along the corresponding axis C. In particular, the thrust means <NUM> comprise a sphere positioner <NUM> comprising a sphere <NUM> designed to enter into a corresponding seat <NUM> under the action of a predetermined force provided by the tip <NUM>.

In particular, the wheel <NUM> comprises a mobile portion <NUM>' defining the above-mentioned seats <NUM> and with which the adjustment system <NUM>, described above, cooperates and a fixed portion <NUM>" borne by the casing 3a and on which the mobile portion <NUM>' is borne rotationally free.

In particular, the mobile portion <NUM>' is integral with a threaded pin <NUM>, for example planted, inside a through opening <NUM> in the mobile portion <NUM>'. The threaded pin <NUM> cooperates by threading with a threaded shaft <NUM> in turn connected, via threading made on the radial internal surface of a through opening <NUM> made within the fixed portion <NUM>".

The integral rotation between threaded pin <NUM> carries with it the rotation of the threaded pin <NUM> that, thus, makes the threaded shaft <NUM> move along the axis A. The threaded shaft <NUM> acts as a stop for the rod 6a so that the maximum opening H of the opening changes in relation to the shaft <NUM> and, thus, as a consequence, the maximum opening of the space between the rod 6a and the opening <NUM> of the nozzle.

The adjustment system <NUM> comprises, in addition, angular timing means <NUM> configured to adjust the relative starting position of the adjustment system <NUM>, i.e., between the movable <NUM>' and the fixed <NUM>" part of the wheel <NUM>.

In particular, the angular timing means <NUM> comprise a positioner <NUM>, for example similar to the positioner <NUM>, configured to cooperate with multiple internal seats made radially corresponding to the seats <NUM>. In addition, the timing means <NUM> comprise a reference dowel <NUM> made on the outside surface of the body 3a.

The timing means <NUM> also comprise an additional reference dowel <NUM> made on the body 3a of the gun <NUM>.

The operation of the adjustment system <NUM> for a painting gun <NUM> described above is the following, referring to <FIG> and to the left actuator <NUM>'.

In <FIG>, a rest condition is illustrated where the tip <NUM> is in the first operating condition. In this condition, there is no pressurised air in the chamber <NUM>'b so as to overpower the force exerted by the elastic means <NUM> that, thus, maintain the second end portion 12b in a predefined rest point. In this condition, the pawl <NUM> does not cooperate in contact with the seat <NUM>.

In <FIG>, a stroke start condition of the tip <NUM> under the action of pressurised air entering the chamber <NUM> is illustrated. In particular, the pressurised air exerts a force that overcomes that exerted by the elastic means <NUM> that tend to compress. Thus, the second end portion 12b tends to enter inside the opening <NUM>. Consequently, the first end portion 12a moves, borne by the second end portion 12b, until the first arm <NUM>' touches one of the walls of the seat <NUM> of the wheel <NUM>. During this step, the thrust means <NUM> impede the rotation of the pawl <NUM> so that the first arm <NUM>' is "hooked" in the corresponding seat <NUM>, i.e., the sphere <NUM> exerts pressure against the second arm <NUM>".

In <FIG>, a rest condition is illustrated where the tip <NUM> is in the second operating condition. In this condition, the pressurised air in the chamber <NUM>' is such that it completely overwhelms the force exerted by the elastic means <NUM> and, thus, the second end portion 12b is in contact with the shoulder between the portions <NUM>' and <NUM>". In this condition, the tip <NUM>, since the pawl <NUM> is hooked into the seat <NUM>, has dragged the wheel <NUM> in its movement, so that the latter rotates around the axis A.

Once the second operating condition, in <FIG>, is reached, the pressurised air is made to flow from the chamber <NUM>. As a consequence, the elastic means <NUM> tend to overwhelm the force exerted by the pressurised air in the chamber <NUM> and to push the second portion 12b towards the position assumed in the first operating condition in <FIG>. During this movement, the arm <NUM>' is unhooked from the corresponding seat <NUM>.

During steps 5B, 5C, the thrust means <NUM> provide a force configured to maintain contact between the tip <NUM> and the pawl <NUM>.

Continuing its movement towards the condition in <FIG>, the thrust means <NUM> come into contact with the single pawl <NUM> (<FIG>) that is pushed by the sphere <NUM> that tends to leave the seat <NUM> exerting a force on the second arm <NUM>". In this way (<FIG>), the pawl <NUM> will be rotated so as to turn in its original position so that it can, again, restart an actuation cycle of the wheel <NUM>.

The operation of the right actuator <NUM>" is the same as the left actuator <NUM>' described above; it is simply a mirror image and, thus, actuates the wheel <NUM> so that it rotates anticlockwise.

As a function of what is described above, the anticlockwise rotation of the wheel <NUM> enables the rotation of the threaded shaft <NUM> and increases the maximum opening H between the end-stop defined by the latter and the rod 6a. In this way, it is possible to increase the flow of painting fluid that can flow between the rod 6a and the opening <NUM> of the nozzle. In contrast, a clockwise rotation of the wheel <NUM> reduces the maximum opening H, potentially reducing this flow of painting fluid to zero.

The correct assembly of the wheel <NUM> is ensured by the angular timing means <NUM>. The positioner <NUM> fulfils the function of maintaining the seats <NUM> in their correct angular position in relation to the tip <NUM>. In contrast, the set of references given by the dowel <NUM> and by the position of the positioner <NUM> itself makes it possible to assemble the wheel <NUM> so as to maintain a prefixed distance between the rod 6a and the opening <NUM> of the nozzle.

Clearly, the actuator means <NUM> can be controlled at the electric-pneumatic level thanks to a control unit, not described, that processes the necessary data for painting an object by means of the painting gun <NUM> and that adjusts, as a result, their activation to provide a correct flow of painting fluid.

From the above, the advantages of the painting gun and the painting system according to the invention are clear.

Thanks to the gun proposed, it is possible to autonomously adjust the flow of liquid through the opening or closing of the adjustment wheel, enabling a fine, singular, and quick adjustment of each, individual gun of a painting system.

The use of pneumatic actuators enables an automatic adjustment and no longer a manual one of the wheel <NUM>, with significant economic advantages given the reduced maintenance time that, in the prior art, was used to manually adjust the guns.

In addition, this invention makes it possible to simply and quickly adjust the flow of liquid delivered by each airbrush device, without the need to interpose additional components subject to maintenance between the paint feeding circuit and the gun. The presence of two actuators per direction of rotation simplifies this pneumatic-mechanical adjustment.

The presence of seats at fixed distances makes it possible adjust in a constant, and therefore calculable way, the opening of the wheel.

The presence of the thrust means facilitates the coupling between pawl and seat and, thus, makes it possible to repeat the operation at high speeds.

Similarly, the presence of the elastic means enables a quick return of the tip to the rest position, enabling a repeated operation at high speeds.

Clearly, the adjustment mechanism proposed for the wheel <NUM> enables extremely fine adjustment of the passage between rod 6a and opening <NUM> of the nozzle that depends on the number of seats <NUM> made on the wheel and the pitch of the threading of the shaft <NUM>. In the example illustrated, comprising, for example, <NUM> seats <NUM> and a threading of one millimetre, it is possible to adjust a vertical distance of the rod of <NUM> from the wheel <NUM>, thus enabling extreme precision.

Thanks to the angular timing means <NUM>, it is also possible to correctly assemble and reassemble the wheel <NUM> without losing the correct calibration of the opening between rod 6a and opening <NUM> of the nozzle.

Finally, it is clear that changes may be made to the painting gun and to the painting system, and variations produced thereto, according to this invention that, in any case, do not depart from the scope of protection defined by the claims.

For example, the type of elastic means and thrust means may vary, just like the shape of the support element, of the pawl or of the tip and of their construction materials.

Claim 1:
- A painting gun (<NUM>) configured to paint an article, said painting gun (<NUM>) defining a housing (3a) extending along a longitudinal axis (A), said housing (3a) configured to house flow regulation means (<NUM>) suitable for regulating the passage of painting fluid coming from a source (<NUM>) of painting fluid,
said painting gun (<NUM>) comprising an adjustment system (<NUM>) for controlling the maximum quantity of painting fluid that can be adjusted by said flow adjustment means (<NUM>)
said flow regulating means (<NUM>) comprising a rod (6a) and an opening (<NUM>) defined by a portion of said gun (<NUM>), said rod (6a) being controlled to move with respect to said opening (<NUM>) and selectively cooperating in contact to close said opening (<NUM>) or to allow the passage of said painting fluid between said opening (7a) and said rod (6a),
said adjustment system (<NUM>) comprising a wheel (<NUM>) configured to rotate around an axis (A) to vary the maximum stroke (H) of said rod (6a) with respect to said opening (<NUM>),
said adjustment system (<NUM>) comprising actuator means configured to act alternatively on said wheel (<NUM>) to rotate it in a first rotation direction around said axis (A) and in a second rotation direction around said axis (A), opposite to the first,
characterized in that said adjustment system (<NUM>) comprises first actuator means (<NUM>') configured to move said wheel (<NUM>) in a direction of rotation around said axis (A) and second actuator means (<NUM>") configured to move said wheel (<NUM>) in an opposite direction to that of said first actuator means (<NUM>"), said first and second actuator means (<NUM>', <NUM>") acting alternatively on said wheel (<NUM>).