Spraying unit and rotating coating product projector including such a spraying unit

Abstract

Spraying unit and rotary coating product projector comprising such a spraying unit. The present invention relates to a spraying unit (30) for a rotary coating product projector (2) which carries at least one mechanically locking weight (40) on a drive shaft (16) of the rotary projector. The weight is movable, radially to the central axis of the bowl (A30) and in a centrifugal direction relative to this axis, between an unlocked position, where it does not oppose the mounting of the spraying unit (30) on the drive shaft (16) or its removal from this shaft, and a locked position where it opposes the removal of the bowl from the drive shaft. Figure for the abstract: Fig 2

Description

Title of the invention: Spraying device and rotating coating product projector comprising such a spraying device

[0001] The present invention relates to a spraying device for a rotating coating product projector, as well as a rotating coating product projector comprising such a spraying device.

[0002] In the field of coating product spraying, WO2005 / 082542A, for example, is a known spray bowl equipped with first magnetic coupling means capable of cooperating with complementary second magnetic coupling means, fixed on a non-rotating part of a spray gun. These first and second coupling means exert an axial force with respect to an axis of rotation of the bowl, which induces a rotational coupling of the bowl and a corresponding drive element.

[0003] This equipment is generally satisfactory.

[0004] However, a problem with this equipment is that the magnetic force between the first and second coupling means must be intense to ensure that the bowl remains in place on the projector, even though the latter may be subjected to significant accelerations when mounted at the end of the arm of a multi-axis robot. This problem is all the more critical when the bowl has a high mass.

[0005] The intensity of the magnetic force between the first and second magnetic coupling means makes it difficult to remove the bowl during maintenance operations. Furthermore, this intensity of the magnetic force can prove dangerous if an operator's finger is pinched during the mounting of the bowl onto the projector.

[0006] Similar problems arise with disc-type spraying elements, that is, spraying elements having an edge whose diameter is generally between 120 and 500 mm. They are exacerbated by the relatively high mass of these discs.

[0007] Similar problems also arise with spraying devices mounted on rotating shafts by coupling means other than magnetic, in particular by screwing, clipping or quarter-turn locking.

[0008] It is these drawbacks that the invention intends to remedy more particularly by proposing a new spraying device, which can be of bowl, disc or other type, whose mounting on a rotating coating product projector is made more reliable, without necessarily having to use coupling means inducing an intense coupling force.

[0009] To this end, the invention relates to a spraying device for a rotating projector of a coating product, characterized in that it carries at least one mechanical locking weight on a drive shaft of the rotating projector, the weight being movable, radially to the central axis of the bowl and in a centrifugal direction relative to this axis, between - an unlocked position, where it does not impede the mounting of the spraying unit on the drive shaft or its removal from that shaft; and - a locked position where it opposes the removal of the bowl from the drive shaft.

[0010] Thanks to the invention, the weight(s) allow the centrifugal force inherent in the rotation of the spraying element around its axis of rotation to be used to lock the spraying element onto the drive shaft. The transition of the weight(s) from its unlocked position to its locked position occurs automatically when the bowl is rotated around its axis of rotation.

[0011] For the purposes of the present invention, a spraying element for a rotary coating product sprayer may be a bowl, a disc, or any other element intended to be driven in rotation to spray a liquid or powdered coating product. Such a spraying element may also be called a bell or cup.

[0012] Given the locking function obtained with the weight(s), a magnetic or mechanical coupling force between the bowl and a drive shaft can be reduced, compared to prior art materials.

[0013] In addition, the reduction of the magnetic force makes it easier to dismantle the spraying element during maintenance operations and reduces the risk of pinching an operator's fingers.

[0014] In the particular case of spray discs, securing the mounting of the disc on the drive shaft allows the use of a conventional drive turbine, of the same type as that used for bowls, the diameter of which is generally between 10 and 100 mm.

[0015] According to advantageous but non-mandatory aspects of the invention, such a spraying device may incorporate one or more of the following features taken in any technically permissible combination:

[0016] - The spraying element is equipped with first magnetic coupling means configured to cooperate with complementary second magnetic coupling means to exert a force at least partially axial with respect to a central axis of the bowl.

[0017] - The spraying element comprises several weights distributed around the axis central, preferably on a regular basis.

[0018] - The spraying element comprises a hub, while each weight is received in a housing formed in the hub and which opens onto an external radial surface of the hub and that, • In its unlocked position, the weight is completely included in the housing; and • in its locked position, the weight protrudes from the housing, beyond the external radial surface of the hub.

[0019] - An opening through which the housing opens onto the external radial surface of the hub has dimensions that prevent the weight from coming out of the housing through this opening.

[0020] - Each weight includes an axial support segment against the shaft the drive and the housing includes a portion of a groove formed on the external radial surface of the hub and which extends, preferably, in an orthoradial direction to the central axis of the bowl, on either side of another portion of the housing in which a guide heel for the weight is engaged.

[0021] - The spraying element comprises a hub and each weight is formed by a single-piece part with the hub and movable from its locked position to its unlocked position by elastic deformation of a part of the hub, under the effect of inertia, when the spraying element is driven in rotation around its central axis.

[0022] - The spraying element includes an elastic return means for the weight to its unlocked position.

[0023] - The elastic return means is an elastically deformable ring which surrounds a hub of the spraying element, at the level of the weight(s) along the central axis of the bowl.

[0024] - The elastically deformable ring is supported on an external radial surface of each segment.

[0025] According to a second aspect, the invention also relates to a rotating coating product projector comprising a spraying element, and a drive shaft rotating the spraying element around an axis of rotation and second magnetic coupling means configured to cooperate with first magnetic coupling means of the spraying element, characterized in that the spraying element is as mentioned above and in that each weight is brought into its locked position due to the rotation of the spraying element by the drive shaft.

[0026] Advantageously, the drive shaft defines a support relief for the or each weight of the spraying element in the locked position and in that, preferably, the support relief is an internal shoulder of the drive shaft.

[0027] The invention will become clearer upon reading the following description, given solely as a non-limiting example, and made with reference to the drawings in which: - [Fig.1] The [Fig.1] is a partial axial section of principle of a projector according to the invention and shows, in external view, a spray bowl according to the invention being mounted on this projector; - [Fig.2] [Fig.2] is a partial axial cross-section of the projector and the bowl of the [Fig.l]; - [Fig.3] The [Fig.3] is a view corresponding to detail III in the [Fig.2] for a projector and a bowl conforming to a second embodiment of the invention, in a first configuration of use; - [Fig. 4] Fig. 4 is a cross-sectional and perspective view of part of the bowl of the second embodiment in the configuration of [Fig.3]; - [Fig. 5] [Fig. 5] is a view analogous to [Fig. 3], when the projector and the bowls are in a second usage configuration; - [Fig. 6] [Fig. 6] represents, on several inserts A), B), C) and D) a section axial with a zoom of a detail, a side view, a perspective section and a partial view of a spray disc according to a third embodiment of the invention, in a first configuration of use; and - [Fig. 7] [Fig. 7] represents the same disk on inserts A), B), C) and D) spraying in a second usage configuration.

[0028] The rotary sprayer or sprayer 2 of coating product shown in Figures 1 and 2 extends along a longitudinal axis A2 and comprises a body 4 formed of a main part 42 and an air distribution plate 44 to an air supply skirt 6 on a face 66 of the skirt 6, into which open channels 62 formed in the air skirt 6. The front face 66 of the air supply skirt 6 is also a front face of the sprayer 2.

[0029] For example, the coating product is a liquid paint, primer or varnish intended to be applied to a body or component of a motor vehicle.

[0030] The projector 2 is of the internally charged electrostatic type and includes a high-voltage unit not shown, configured to bring to a given electrical potential the coating product sprayed by the projector 2.

[0031] A front side of the projector 2 or of a component thereof is defined as a side facing a workpiece to be coated, during the operation of the projector 2, and a rear side as a side facing away from the front side. In Figures 1 and 2, the front of the projector 2 is facing upwards and the rear is facing downwards.

[0032] Pawns 46 allow elements 42, 44 and 6 to be joined and oriented relative to each other.

[0033] The projector 2 also includes an air turbine 8 which itself includes a stator 10 and a rotor 12 which carries fins 122 subjected to the action of a driving airflow in rotation of the rotor 12 around the longitudinal axis A2.

[0034] The body 4 and the stator 10 are joined together by means of screws 13 which pass through the elements 44, 42 and 10.

[0035] A rotating shaft 16 is fixed to the rotor 12 and rotates with it around the longitudinal axis A2, which forms an axis of rotation for the rotor 12 and the rotating shaft 16.

[0036] The rotating shaft 16 is equipped with a frustoconical surface 162 centered on the longitudinal axis A2 and which diverges forward.

[0037] The rotating shaft 162 is hollow and defines a central bore 164 in which is disposed a coating product injector 18 which is supported by a plate 20 on which are mounted the body 4 and the turbine 8 of the projector 2.

[0038] The stator 10, which does not rotate around the axis A2 during use of the projector 2, is equipped with a support 102 on which is mounted a permanent magnet 22 of annular shape centered on the longitudinal axis A2.

[0039] A central bore 164 of the rotating shaft 16 comprises a first front portion 164A defined radially by the frustoconical surface 162 and a second rear portion 164B defined by a cylindrical surface with a circular base 166, also centered on the axis A2.

[0040] The minimum diameter of the frustoconical surface 166 is less than the diameter of the cylindrical surface 166. Thus, a rearward facing shoulder 168 is defined in the bore 164, at the junction between its front and rear portions 164A and 164B.

[0041] A spray bowl 30 according to the invention is provided to be mounted on the projector 2. The spray bowl 30 is centered on a central axis A30 which coincides with the longitudinal axis of rotation A2 in the mounted configuration of the bowl 30 on the projector 2.

[0042] The spray bowl 30 includes a front portion 32, which defines a surface 322 for distributing a liquid coating product up to a spray edge 324 forming a front end of the bowl 30. The spray bowl 30 also includes a hub 34 for engaging in the central bore 164 of the rotating shaft 16. An external peripheral surface 342 of the hub 34 is configured to bear surface-bearing on the frustoconical surface 162 of the rotating shaft 16, thus ensuring rotational rigidity, around the coincident axes A2 and A30, of the spray bowl 30 and the rotating shaft 16.

[0043] The spray bowl 30 is equipped with a deflector 36 which is screwed into the hub 34 and which allows to divert a flow of liquid coating product exiting the injector 18 towards the distribution surface 322.

[0044] The spray bowl 30 is also equipped with a ring 38 made of a ferromagnetic material and intended to interact with the magnet 22.

[0045] For example, the ring 38 can be made of steel, while the front portion 32 and the hub 34, which are monoblocs, are made of aluminium.

[0046] In a non-represented variant of the invention, the front portion 32 and / or the hub 34 are made of a ferromagnetic material and a part corresponding to the ring 38 is monobloc with one or the other of these elements.

[0047] The ring 38 defines an annular surface 382 perpendicular to the central axis A30 which is arranged opposite the permanent magnet 22 in the mounted configuration of the bowl 30 on the projector 2.

[0048] In this configuration, a magnetic flux from the permanent magnet 22 closes in the ferromagnetic material ring 38, which has the effect of exerting a coupling force El globally parallel to the axes A2 and A30 coincident, this force having the effect of firmly pressing the external peripheral surface 342 onto the frustoconical surface 162, which locks the spray bowl 30 and the rotating shaft 16 in rotation.

[0049] During operation of the projector 2, and insofar as the permanent magnet 22 is fixed relative to the body 4, while the spray bowl 30 must be able to rotate, an axial gap must be created between the elements 22 and 38. This is achieved by injecting an airflow between a rear surface 163 of the rotating shaft 16 and a front surface 203 of the plate 20, which has the effect of creating an air bearing between the parts 16 and 20. For clarity of the drawing, this air bearing is not shown in [Fig. 2] where the surface 382 is shown bearing against a front surface 222 of the magnet 22.

[0050] In summary, the ring 38 forms first magnetic coupling means and the permanent magnet 22 forms second magnetic coupling means which exert the axial magnetic force El, inducing a rotational coupling of the bowl 30 and the rotating shaft 16. Meanwhile, an airflow (not shown) creates an air bearing between the rotating shaft and a fixed part of the projector 2, which has the effect of pushing the rotating shaft 16 and the bowl 30 carried by the rotating shaft forward. The result is an axial gap created between the surfaces 222 and 382, ​​which allows the bowl 30 to rotate about the axis of rotation A2.

[0051] Here, the force El is purely axial with respect to the axis of rotation A2. In a non-represented variant of the invention, the force El is partially axial with respect to this axis of rotation, i.e. inclined with respect to it, as envisaged in WO2005 / 082542A.

[0052] The hub 34 is pierced with six housings 344 which open onto the peripheral surface 342, each through a first orifice 344A.

[0053] Inside each of the housings 344 is arranged a weight 40 which, in the example of figures 1 and 2, is a ball whose diameter is denoted ¢40.

[0054] Each first orifice 344A is circular in shape and its diameter is denoted ¢344.

[0055] The diameter ¢344 is slightly smaller than the diameter ¢40, for example by 10%, so that the balls 40 are not likely to be ejected from the housings 344 through the first orifices 344A, including under the action of centrifugal force when the spray bowl is driven in rotation around the axis of rotation A2 by the rotating shaft 16.

[0056] In the case of a weight 40 having, alternatively, a shape other than circular, the geometry of the housing 344 and the orifice 344A are adapted. In all cases, the dimensions of the orifice 344A prevent the weight 40 from exiting the housing 344 through this orifice.

[0057] On the other hand, each housing 344 opens, through a second orifice 344B opposite its first orifice 344A, into a central bore 346 of the hub 34. When screwed into the hub 34, the deflector 36 partially closes each second orifice 344B, so that the weights 40 cannot come out of their housing 344 by engaging completely in the central bore 346.

[0058] At rest, i.e. when the turbine 8 is not in operation, the spray bowl 30 does not rotate about the axis of rotation A2 and the weights 30 can take any position in their housing 344, between the ports 344A and 344B. In particular, they can be fully engaged in these housings 344, as shown on the left of [Fig. 2], in which case they do not prevent the spray bowl 30 from being placed on the rotating shaft 16, nor from being removed.

[0059] In operation of the spraying device 2, when the spraying bowl is driven in rotation around the axis of rotation A2, with a rotational speed of several thousand revolutions per minute, the centrifugal force which is exerted on the weights 40 has the effect of moving them to the configuration shown on the right of [Fig.2] where each of these weights protrudes, through the first orifice 344A of the corresponding housing 344, relative to the peripheral surface 342.

[0060] In the embodiment shown in Figures 1 and 2, the housings 344 each extend in a radial direction to the central axis A30 and perpendicular to this axis. The weights move in this direction.

[0061] In an alternative embodiment of the invention, not shown, the housings extend along directions inclined towards the front of the bowl 3, along which the weights 40 move under the effect of centrifugal force. Advantageously, an angle of inclination between the longitudinal directions of the housings 344 and a plane perpendicular to the central axis A30 is between 0 and 45°, preferably between 0 and 30°.

[0062] By thus protruding from the peripheral surface 342, each weight 40 comes into contact with the shoulder 168, so that it opposes the extraction of the bowl 30 from the rotating shaft 16, in a direction opposite to that of the force EL

[0063] Thus, the weights formed by the balls 40 secure the attachment of the bowl 30 to the rotating shaft 16 as soon as the rotating projector 2 drives the bowl 30 in rotation around its axis of rotation A2. A mechanical locking force due to the interaction of the balls 40 and the shoulder 168 is thus added to the magnetic force El between the first and second magnetic coupling means 38 and 22, when the spray bowl 30 is driven in rotation by the rotating shaft 16, around the axis of rotation A2. The intensity of the magnetic force El can therefore be reduced compared to the intensity of a similar force in prior art equipment.

[0064] Under these conditions, the operation of the projector 2 is made reliable and the mounting of the spray bowl 30 on the rotating shaft 16 is permanent, even if the magnet 22 develops a relatively weak magnetic force on the ferromagnetic ring 38. The use of the weights 40 therefore makes it possible to reduce the size, and therefore the mass and the cost, of the permanent magnet 22 as well as the air flow required to create an air bearing between the surfaces 222 and 382.

[0065] When the projector 2 is switched off, the centrifugal inertial forces no longer act on the weights 40, which can then return to a position such as that shown on the left of [Fig. 2], where they do not oppose the extraction of the spray bowl 30 from the rotating shaft 16, under the effect of a force opposite to the magnetic force EL

[0066] As this magnetic force El is less important than in the prior art, due to a lesser magnetic interaction between the elements 22 and 38, the effort required to remove the spray bowl 30 is less important.

[0067] In addition, as the magnetic force El between the elements 22 and 38 is less important than in the prior art, there is less risk for the user of injury when placing the spray bowl 30 on the projector 2, in particular by pinching their finger under the effect of the attraction between the parts 22 and 38.

[0068] In the second and third embodiments of the invention shown in [Fig. 3] and following, the elements analogous to those of the first embodiment bear the same reference numerals. In what follows, if a reference numeral is mentioned in the description but not shown in one of Figures 3 to 7, or shown in one of these figures but not mentioned in the corresponding description, it designates the same element as in the first embodiment.

[0069] In the foregoing, we mainly describe what distinguishes the second embodiment from the first embodiment.

[0070] In the second embodiment, the balls 40 of the first embodiment are replaced by weights 140 which each include a heel 142 and a circular arc segment 144.

[0071] Each heel 142 is oblong in shape, with its longest dimension parallel to the central axis A30 in the mounted configuration of the weight on the bowl 30. Each segment 144 extends over an angular amplitude of approximately 120° around the axis A30 in the mounted configuration of the weight 40 on the bowl 30.

[0072] In the example of figures 3 to 5, the bowl 30 is equipped with three weights, hence the value of 120° for the angular amplitude of segments 144.

[0073] Alternatively, the number of weights 140 is different, for example equal to one, two, four or six, in which case the angular amplitude of the segments 144 is adapted, for example equal to 180°, 90° or 60°.

[0074] Preferably, the number of weights 40 is strictly greater than one and they are distributed around the central axis A30.

[0075] In this case, the weights are advantageously regularly distributed around the central axis A30, which makes it possible to balance a locking force of the bowl 30 on the rotating shaft, obtained with these weights and explained below.

[0076] Each weight 140 extends in a housing 344 which includes a first central portion 344C, which goes through the hub 34 and is intended to receive the heel 142, and a second peripheral portion 344D, in a peripheral groove segment formed on the peripheral surface 342 of the hub 344 and which is intended to receive the segment 144.

[0077] In other words, the three segments 144 of the three weights 140 which equip the bowl 30 of the embodiment of figures 4 to 5 together occupy an external annular groove 348 of the hub 34, this peripheral groove 348 extending over 360° around the central axis A30 and being formed by the meeting of the three second portions 344D of the three housings 344 configured to receive the segments 144.

[0078] The cooperation of the portions 344C and the heels 142 allows each weight 140 to be guided in translation along a radial direction to the axis A30.

[0079] Each segment 144 is provided with an external peripheral groove 144A which extends over the entire angular amplitude of the segment. The union of the peripheral grooves 144A forms an annular groove 146, which extends over 360° around the central axis A30.

[0080] On the other hand, an O-ring 150 is engaged in the annular groove 146.

[0081] The O-ring 150 surrounds the hub 34 of the spray bowl 30, at the level of the weights 140 and housings 344. It is supported against the bottom of the annular groove 146, which is formed by the meeting of the bottoms of the external peripheral grooves 144A of the segments 144 which are external radial surfaces for these segments.

[0082] The diameter of the seal 150 is chosen so that it presses the weights 140 by default towards their most recessed position in the housings 344, this position being that shown in figures 3 and 4. In this position, the internal radial surfaces of the segments 144 are in contact with the bottoms of the second portions 344D of the three housings 344.

[0083] In this position, the weights 140 and the O-ring 150 do not protrude radially from the peripheral surface 342 of the hub 34, so that the weights 140 do not oppose the mounting of the spray bowl 30 on the projector 2 or its removal.

[0084] In this position, the weights 140 are each in an unlocked position.

[0085] When the projector 2 is operating and rotating the bowl 30 around the axis of rotation A2, the weights 140 subjected to the centrifugal inertial forces move radially to the axis A2, in the housings 344, to reach the configuration of [Fig.5] where their segments 144 protrude radially from the external peripheral surface 342 of the hub 34 and are aligned, in a direction parallel to the axis A2 with the internal shoulder 168 of the rotating shaft 16.

[0086] Thus, depending on whether the bowl 30 is driven in rotation or not, the segments 144 selectively come into contact with the shoulder 168 and, where applicable, bear against it. The segments 144 are axial support segments against the drive shaft 16.

[0087] In this configuration, the weights 140 oppose a tearing movement of the bowl 30 relative to the rotating shaft 16, in a direction opposite to that of a magnetic force El defined as in the first embodiment.

[0088] As soon as the rotation of the bowl 30 is stopped, the elastic force applied by the O-ring 150 on the weights 140 returns these weights to their unlocked configuration of figures 3 and 4. The O-ring 150 therefore ensures that the weights move to the unlocked configuration as soon as the rotation of the bowl 30 stops.

[0089] Furthermore, it is not necessary for the housings 344 to have openings opening onto the peripheral surface 342 with dimensions smaller than the dimensions of the weights 140 since the seal 150 opposes a complete exit of the weights 140 relative to these housings.

[0090] On the other hand, the shape of the segments 144, which have a width along an orthoradial direction to the central axis A30 greater than the orthoradial dimension of the portions 344C opposes a migration of the weights 144 towards the central bore 346.

[0091] In this regard, the fact that the sum of the angular sectors over which the different segments 144 extend is approximately equal to 360° also makes it possible to prevent the weights 144 from engaging in the central bore 346.

[0092] In the third embodiment shown in figures 6 and 7, the spraying member 30 is a spraying disc which also includes a front portion 32 and a hub 34 which defines three housings 344 each formed of two portions 344C and 344D.

[0093] The weights 140 are identical to those of the second embodiment and each comprise a panel 142 and a segment 144.

[0094] The dwellings 344 are identical to those of the second embodiment and each comprise a first central portion 344C and a second peripheral portion 344D.

[0095] Each segment 144 defines a peripheral groove 144A which forms part of an annular groove 146. An O-ring 150 is engaged in this annular groove as seen, in particular, on the inserts D of figures 6 and 7.

[0096] In the rest configuration shown in [Fig.6], the weights 140, particularly their segments 144, do not protrude radially from the housings 344, beyond the peripheral surface 342, so that they do not oppose the placement of the spray disc 30 on the rotating shaft of a projector comparable to the projector of the first and second embodiments.

[0097] In the configuration of [Fig.7], the spray disc 30 is assumed to rotate, to the point that the centrifugal force exerts on the weights 140 a radial force on the central axis A30 which causes the segments 144 to partially come out of the housings 344, more particularly of the second portions 344D of these housings, so that these segments oppose a withdrawal of the spray disc from the rotating shaft of the projector, according to an operation comparable to that described above concerning the second embodiment.

[0098] As can be seen on insert D of [Fig.7], under the action of centrifugal force, the segments 144 of the weights 140 may no longer be joined, whereas they are in the unlocked configuration of [Fig.6].

[0099] In practice, in the second and third embodiments, the O-ring 50 is made of elastomer, in particular fluorinated rubber, of type FKM, nitrile, ethylene-propylene-diene monomer (EPDM) or other rubber.

[0100] In a non-represented variant of the invention, in the second and third embodiments, the O-ring 50 can be replaced by an elastically deformable cord, a rod, of square or other section and of solid or hollow section.

[0101] According to another unrepresented variant of the invention, an elastic return means comparable to the O-ring 150 can be used in the first embodiment.

[0102] According to a non-represented variant of the invention, in the second and third embodiments, the weights 140 are without a heel 142. In this case, the housings 344 are without a first central portion 344C and the guidance of the weights 140, in radial translation with respect to the central axis A30, is not carried out by the cooperation of the parts 144 and 344D, accommodating a possible rotation of the segments 144 around the axis A30.

[0103] According to another variant, there is no elastic return element for the weights 140 in their unlocked configuration. In other words, the O-ring 150 is not present in the second and third embodiments.

[0104] The shape of the weights shown in the figures is not limiting and the weights can take other shapes, compatible with their movement between their unlocked position and their locked position under the effect of the centrifugal inertial forces due to the rotation of the spraying member 30. The shape of the housings 344 is adapted to that of the weights 40 and 140. For example, the weights can take one of the following shapes: parallelepiped, ogive or hemisphere.

[0105] According to a non-represented embodiment of the invention, each weight is formed by a single piece with the hub 34. Such a single piece can be made by machining the hub or by additive manufacturing and is connected to the hub by an elastically deformable tab which is also single piece with the hub, which connects the weight to a main part of the hub and which allows the weight to move radially to the central axis A30 under the effect of centrifugal force, when the spraying element is driven in rotation around its central axis A30.

[0106] The invention is described above in the case where a magnetic coupling force El is used to clamp the spraying element 30 onto the rotating shaft 16 and where the locking achieved with the weights makes it possible to limit the intensity of this force EL

[0107] According to a non-shown embodiment of the invention, the rotational coupling of the bowl and the rotating shaft is achieved by screwing. In this case, the locking effect obtained with the weights makes it possible to limit the screwing torque to be applied to couple the bowl and the rotating shaft.

[0108] According to another, unshown, embodiment of the invention, the rotational coupling of the bowl and the rotating shaft is achieved by quarter-turn locking, in particular with bayonets. In this case, the locking achieved with the weights makes it possible to limit the tightening torque to be applied to couple the bowl and the rotating shaft.

[0109] According to another, unshown, embodiment of the invention, the rotational coupling of the bowl and the rotating shaft is achieved by clipping, in particular according to the technical teaching of WO94 / 12286A. In this case, the locking achieved with the weights makes it possible to limit the rigidity of a clipping element, which facilitates the placement of the bowl on the rotating shaft.

[0110] In all cases, the locking obtained with the weights makes it possible to make the coupling of the bowl on the rotating shaft reliable when achieved by other magnetic and / or mechanical means.

[0111] Alternatively and regardless of the embodiment, projector 2 is of the externally charged electrostatic type and includes a high-voltage unit and charging electrodes not shown, configured to bring to a given electrical potential the coating product sprayed by the projector 2.

[0112] According to another variant applicable to all embodiments, the projector 2 is not of the electrostatic type.

[0113] Alternatively, instead of a single annular permanent magnet 22, several permanent magnets distributed around the axis of rotation can be used as magnetic coupling means.

[0114] The invention is described above in the context of its use for spraying liquid coating products. It also applies to spraying powdered coating products.

[0115] Any feature described for an embodiment or variant in the foregoing may be implemented for the other embodiments and variants mentioned above, provided that it is technically feasible.

Claims

Demands

1. Spraying element (30) for a rotating coating product projector (2), characterized in that it carries at least one mechanical locking weight (40; 140) on a drive shaft (16) of the rotating projector, the weight being movable, radially to the central axis of the bowl (A30) and in a centrifugal direction relative to this axis, between - an unlocked position, where it does not oppose the mounting of the spraying element (30) on the drive shaft (16) or its removal from this shaft; and - a locked position where it opposes the removal of the bowl from the drive shaft.

2. Spraying member according to claim 1, characterized in that it is equipped with first magnetic coupling means (38) configured to cooperate with second complementary magnetic coupling means (22) to exert at least partially axial force (El) with respect to a central axis (A30) of the bowl.

3. Spraying device according to any one of the preceding claims, characterized in that it comprises several weights (40; 140) distributed around the central axis (A30), preferably in a regular manner.

4. A spraying device according to any one of the preceding claims, characterized in that it comprises a hub (34), in that each weight is received in a housing (344) formed in the hub and which opens onto an external radial surface (342) of the hub and in that, - in its unlocked position, the weight (40; 140) is completely included in the housing (344); and - in its locked position, the weight (40; 140) protrudes from the housing (344), beyond the external radial surface (342) of the hub (34).

5. Spraying member according to claim 4, characterized in that an orifice (344A) through which the housing (344) opens onto the external radial surface (342) of the hub has dimensions (¢344) preventing the weight (40) from exiting the housing through this orifice.

6. Spraying element according to claim 4, characterized in that each weight (140) includes an axial support segment (144) against the drive shaft (16) and in that the housing includes a portion of a groove (344D) formed on the external radial surface (342) of the hub and which extends, preferably, in an orthoradial direction to the central axis of the bowl (A30), on either side of another portion of the housing (344C) in which a weight guide heel (142) is engaged.

7. Spraying member according to any one of claims 1 to 3, characterized in that it comprises a hub (34) and in that each weight is formed by a single part with the hub and movable from its locked position to its unlocked position by elastic deformation of a part of the hub, under the effect of inertia, when the spraying member is driven in rotation around its central axis.

8. Spraying device according to any one of the preceding claims, characterized in that it comprises a means (150) for elastically returning the weight (40; 140) to its unlocked position.

9. Spraying member according to claim 8, characterized in that the elastic return means is an elastically deformable ring (150) which surrounds a hub (34) of the spraying member (30), at the level of the weight(s) (40; 140) along the central axis (A30) of the bowl.

10. Spraying element according to claims 6 and 9, characterized in that the elastically deformable ring (150) is supported on an external radial surface (144A) of each segment.

11. Rotating coating product sprayer (2) comprising a spraying member (30) and a drive shaft (16) for rotating the spraying member about an axis of rotation (A2), characterized in that the spraying member (30) is according to one of the preceding claims and in that each weight (40; 140) is brought into its locked position due to the rotation of the spraying member by the drive shaft (16).

12. Projector according to claim 11, characterized in that the drive shaft (16) defines a support relief (168) for the or each weight (40; 140) of the spraying member in the locked position and in that, preferably, the support relief is an internal shoulder (168) of the drive shaft.

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