Patent Application
20170266672
The present invention relates to a coating sprayer, provided to be mounted at the end of the arm of a multiaxial robot, with a to-and-fro manipulator more commonly called a reciprocator, or with a fixed unit. Multiaxial robots are in particular used on automobile painting lines to deposit a coating, such as a primer, varnish or paint.
In order to obtain automation in the form of fine droplets and good control of the jet, some sprayers are equipped with a high-speed turbine, which rotates a bowl around a spraying axis. Furthermore, a skirt is fastened on the stator of the turbine to diffuse an air jet inside and/or outside the cloud of coating product, so as to stabilize this cloud. This skirt has two parts: it comprises an inner part and an outer part that are arranged to diffuse “straight” and/or “vortex” air.
The skirt is the component of the sprayer that makes it possible, inter alia, to adjust the size of the impact and to obtain a stable and regular spraying quality. The skirt is mounted in the immediate vicinity of the rotary bowl. It is therefore very exposed to the cloud of coating product and must therefore be disassembled and cleaned regularly. As an example, in a production organization system using three eight-hour shifts, the skirt must be disassembled and cleaned upon each change of station, or every eight hours.
In a known manner, the skirt is fastened on the body of the sprayer either by directly screwing the outer part of the skirt on the body of the sprayer, or using a special nut that is screwed on the body of the sprayer and that maintains the skirt via a shoulder. The skirt is traversed by independent compressed air circuits. Often, these independent circuits include one or several directional air circuits, called “straight” air, one or several additional air circuits, called “vortex” air, and one or several cleaning solvent circuits. A skirt therefore comprises between five and eight independent circuits, which are connected to complementary circuits defined in the body of the sprayer. The skirt must therefore be positioned angularly relative to the body of the sprayer in a predefined manner. This predefined angular position is maintained by an additional component, such as a radial pin. The radial pin makes cleaning operations complicated and tedious, since many sealing gaskets must be changed periodically.
Furthermore, when the skirt is screwed on the body of the sprayer, a very fine screw pitch should be used in order to obtain good sealing at the junction between the body of the sprayer and the skirt. As an example, for a diameter comprised between 90 mm and 140 mm, the screw pitch is comprised between 0.8 mm and 2 mm. This very fine screw pitch requires special attention during the assembly and disassembly of the skirt. Indeed, an incorrect alignment of the threads during the screwing or unscrewing of the skirt can damage the parts. Furthermore, for weight and safety reasons, the means used to keep the skirt in its predefined angular position are generally made from plastic or a light metal alloy. However, these materials do not tolerate successive assembly and disassembly operations well, since coating residue may infiltrate the threads of the skirt and/or the body of the sprayer, which can cause material to pull out and partial or total destruction of the sprayer.
The invention more particularly intends to resolve these drawbacks by proposing a coating sprayer with which the successive assembly and assembly operations of the skirt do not damage the components of the sprayer.
To that end, the invention relates to a sprayer intended to be mounted on a robot and comprising an air guiding element and means for fastening the air guiding element on a fixed member of the sprayer. According to the invention, the fastening means comprise at least one magnetic attraction means mounted on a first component from among the air guiding element and the fixed member and at least one part made from a ferromagnetic material, which is intended to cooperate with the magnetic attraction means and which is mounted on or formed by the other component from among the air guiding element and the fixed element.
US 2003/234299 discloses several embodiments of a coating sprayer. The sprayer comprises a body defining a portion for receiving a sprayer unit and a portion for receiving a cartridge. This sprayer is specific in that it comprises magnetic fastening means to fasten the cartridge to the inside of the portion of the body. These magnetic fastening means can comprise permanent magnets or electromagnets. The spraying unit comprises an air guiding element, defining air discharge holes. The cartridge is provided to be replaced, and is therefore completely removable. It therefore cannot be considered a fixed member of the sprayer within the meaning of the invention. Furthermore, the magnetic fastening means mentioned in this publication are used to fasten the cartridge to the inside of the portion provided in the body, and not to fasten the air guiding element with the fixed body of the sprayer.
WO 2013/191323 discloses several embodiments of a spraying head for a sprayer device. In the first embodiment, the spraying head comprises a nozzle defining a fluid discharge passage and an air guiding element, which comprises two diametrically opposite horns, to generate atomizing air jets. The spraying head is fastened to a body of the gun. To that end, the gun comprises a pair of elastic tongues provided with respective openings. When the body of the gun and the spraying head are engaged in one another, the elastic tongues are elastically outwardly deformed until stops provided on the spraying head penetrate the inside of the openings. Page 7, lines 27 to 30, states that such fastening means could be replaced by magnets. The magnets mentioned in this passage of the description do not form means for fastening the air guiding element on a fixed member of the sprayer. In fact, the magnets relate to the fastening of the spraying head on the body of the gun. Furthermore, the stops are provided on a barrel on which the air guiding element is fastened. In particular, the air guiding element can be fastened rigidly or pivoting on the barrel. Furthermore, the disclosed material more particularly applies to a manual gun for applying a coating, and not a sprayer intended to be mounted on a robot.
Owing to the invention, the air guiding element can be assembled and disassembled without any risk of damaging the components of the sprayer, since no thread is used.
According to advantageous, but optional aspects of the invention, such a sprayer may include one or more of the following features, considered in any technically allowable combination:
The fixed member of the sprayer is a turbine stator, while each ferromagnetic part is mounted on the air guiding element, and each magnetic attraction means is mounted on the stator.
The magnetic attraction means is received in a recess defined in a shoulder of the stator, while each ferromagnetic part is received in a recess of the air guiding element, this recess being defined in a complementary shoulder of the air guiding element.
The fixed member of the sprayer is a turbine stator, while each ferromagnetic part is mounted on the stator, and each magnetic attraction means is mounted on the air guiding element.
Each magnetic attraction means is received in a recess defined in a shoulder of the air guiding element, while each ferromagnetic part is received in a recess of the stator defined in a complementary shoulder of the stator.
The fixed member of the sprayer is a turbine stator, while the air guiding element or the stator of the turbine is made from a ferromagnetic material.
The sprayer comprises orientation means, to orient the air guiding element automatically relative to the fixed member in a predefined angular position.
The orientation means comprise at least one pin and at least one corresponding notch or slot to receive the pin.
Each notch or slot is configured so that the air guiding element can rotate around a central axis relative to the fixed member when the pin is moved in the corresponding notch or slot.
Each notch or slot extends at least partially in a helical direction around the central axis.
The pitch of each notch or slot around a spraying axis is to the right seen from the side opposite the fixed member.
The pitch of each notch or slot around a spraying axis is to the left seen from the side opposite the fixed member.
Each notch is defined by the air guiding element, while each pin is supported by the fixed member.
Each slot is defined by the fixed member, while each pin is supported by the air guiding element.
Each pin does not protrude radially relative to the outer surface of the air guiding element.
The invention also relates to a method for assembling an air guiding element on a fixed member of a sprayer as previously described. This method consists of moving the air guiding element and the fixed member relative to one another until reaching a position in which the air guiding element is fastened to the fixed member by cooperation of the magnetic attraction means with the ferromagnetic part.
The invention lastly relates to a method for disassembling an air guiding element from a fixed member of a sprayer as previously described. The method consists of moving the air guiding element and the fixed member relative to one another until reaching a position in which the magnetic attraction means no longer cooperates with the ferromagnetic part.
Advantageously, but optionally, the relative movement between the guiding element and the fixed member during the assembly or disassembly is a translational movement along the central axis and/or a rotational movement around the central axis.
Advantageously, but optionally, the relative movement between the guiding element and the fixed member is a translational movement along the central axis and a tool bearing a wedge is used to separate the guiding element and the fixed member from one another axially during the disassembly.
The invention and other advantages thereof will appear more clearly in light of the following description of two embodiments of a sprayer according to its principle, provided solely as an example and done in reference to the appended drawings, in which:
Advantageously, the sprayer 1 is an electrostatic sprayer.
The sprayer 1 locally has a geometry of revolution around an axis X-X′, which forms a spraying axis for the coating product. The sprayer 1 comprises a body 3 shown diagrammatically in mixed lines in
In the present application, a front direction designates an axial direction parallel to the axis X-X′ that is oriented in the spraying direction, i.e., to the left in
A shoulder 20 decreases the outer diameter of the stator 2 of the turbine going forward. The turbine stator 2 defines a central bore 22 for receiving the rotor. The shoulder 20 of the stator 2 defines an annular surface perpendicular to the axis X-X′. This annular surface includes at least one recess 24, in which a magnetic attraction means 6 is received. In the example, this magnetic attraction means is a permanent magnet.
Advantageously, the stator 2 defines three recesses 24 that are distributed regularly around the axis X-X′ and that each receive a magnet 6. The strength of the magnets 6 is sufficient to crush the sealing gaskets between the skirt and the body and to thus provide good sealing. This strength is comprised between 10 kN and 200 kN, preferably about 100 kN, relative to pulling out in the axial direction.
In the example, the magnets 6 are ring portions. However, the shape of the magnets 6 is not limiting. Thus, the magnets 6 can assume any shape suitable for the geometry of the sprayer, such as a shape with a square, rectangular, circular or elliptical section.
The stator 2 comprises at least one pin that protrudes radially outward relative to its outer surface of the stator 2. In the example, the stator 2 comprises three pins, among which two pins are referenced 26a and one pin is referenced 26b. The two pins 26a are the pins that are least spaced apart from one another. Only one of these two pins 26a is visible in
The stator 2 defines holes 21, two of which are visible in
The stator 2 is traversed by independent circuits 28, eight of which are visible in
An air guiding element 4 is fastened on a fixed member of the sprayer 1. In the example, this element is a skirt and the fixed member is the stator 2 of the turbine. Advantageously, the skirt comprises an inner part 4a and an outer part 4b screwed around the inner part 4a. As an alternative that is not shown, the skirt 4 is in a single piece. The skirt 4 has a geometry of revolution the axis X-X′. The inner part 4b of the skirt 4 includes a shoulder 40 complementary to the shoulder 20 of the stator 2 of the turbine. Thus, the shoulders 20 and 40 are in contact with one another in the mounted configuration of the skirt 4. The shoulder 40 decreases the inner diameter of the skirt 4 in the forward direction. The shoulder 40 forms a surface perpendicular to the axis X-X′ defining at least one recess 44 in which a part 8 is housed made from a non-magnetized ferromagnetic alloy. In the example, the stator 2 defines three recesses 44. There are therefore as many magnets 6 as there are ferromagnetic parts 8. Thus, each magnet 6 cooperates with a corresponding part 8 to fasten the skirt 4 to the stator 2 of the turbine. The magnets 6 and the ferromagnetic parts 8 therefore together form fastening means for fastening the skirt 4 on the stator 2 of the turbine. Fastening the skirt 4 using magnetization makes it possible to eliminate the use of very fine screw pitches, which require special attention during the assembly and disassembly of the skirt 4 and are subject to deterioration.
The inner part 4b of the skirt 4 protrudes axially toward the rear relative to the outer part 4a. It therefore comprises a protruding rear portion, which defines at least one notch. In the example, the inner part 4b of the skirt 4 defines three notches, among which two notches are referenced 42a and one notch is referenced 42b. There are therefore as many notches as there are pins. The two notches 42a are those that are least spaced apart from one another. The notches 42a and 42b are therefore distributed irregularly around the axis X-X′. The notches 42a are respectively provided to guide the pins 26a during the fastening of the skirt 4 on the stator 2, while the notch 42b is provided to guide the pin 26b.
Each notch 42a and 42b advantageously has a length comprised between 10 mm and 50 mm, preferably about 20 mm.
Advantageously, each notch 42a, 42b is configured such that the skirt 4 can rotate around the axis X-X′ and relative to the stator 2 when the corresponding pins 26a, 26b are moved in the notches 42a, 42b. This procures the advantage of making the skirt 4 easier to disassemble, since the forces necessary to separate the skirt 4 and the stator 2 from one another are lower relative to a configuration where the skirt is detached from the stator 2 by a purely axial movement.
Advantageously, each notch 42a or 42b extends along a helical direction around the central axis X-X′, with a helix angle θ comprised between 5° and 75°, in particular about 60° . This angle θ is measured relative to a direction orthoradial to the axis X-X′. In the example, the pitch of each notch 42a and 42b around the axis X-X′ is to the right seen from the side opposite the fixed member 2, i.e., seen from the left in
However, as an alternative that is not shown, the notches 42a and 42b extend in a different direction. For example, the notches 42a and 42b can extend parallel to the axis X-X′, obliquely or bent. It is also possible to consider an embodiment where the notches extend, toward the front from the rear edge of the skirt 4, first in an axial direction, then in an oblique, helical or curved direction.
Advantageously, the portion of the part 4a of the skirt that defines the notches 42a and 42b has a radial thickness substantially equal to the height of the pins 26a and 26b, such that the pins 26a and 26b do not protrude radially outward in the assembled configuration of the sprayer 1. Each pin 26a and 26b therefore does not protrude radially relative to the outer surface of the skirt 4. The pins 26a and 26b therefore do not generate turbulence during the movement of the robot.
The skirt 4 defines independent circuits, complementary to the circuits 28 defined in the stator 2; that is why the angular position of the skirt 4 around the axis X-X′ relative to the stator 2 of the turbine is predefined. Otherwise, the circuits of the skirt 4 would not be connected to those defined in the stator 2 of the turbine.
To mount the skirt 4 manually on the stator 2 of the sprayer 1, the two elements should be brought axially closer to one another until reaching a position in which the air guiding element 4 is fastened to the fixed member 2 by cooperation of the magnetic attraction means 6 with the ferromagnetic part 8.
More specifically, the skirt 4 is oriented around the axis X-X′ so as to align the pins 26a with the notches 42a and the pin 26b with the notch 42b. The position of the notches 42a and 42b then forms mechanical mistake-proofing means preventing the operator from making a mistake when assembling the skirt 4 on the stator 2. The pins 26a and 26b of the stator 2 them penetrate the corresponding notches 42a and 42b of the skirt 4. The notches 42a and 42b are configured so that the skirt rotates automatically around the axis X-X′ as the pins 26a and 26b penetrate toward the bottom of the corresponding notches, i.e., as one brings the skirt 4 and the stator 2 of the turbine close together. The ferromagnetic parts 8 are attracted by the magnets 6 and the pins 26a and 26b arrive at the bottom of the notches 42a and 42b. The skirt is then oriented in the predefined angular position, in which a sealed connection can be made between the respective circuits of the skirt 4 and the stator of the turbine 2. The notches 42a, 42b and the pins 26a, 26b therefore form means for automatically orienting the skirt around the axis X-X′ in a predefined angular position relative to the stator 2 of the turbine.
The skirt 4 can also be mounted automatically using the movement of the multiaxial robot. In this case, the skirt 4 is mounted on a support on which it is immobilized in rotation around its axis X-X′, but freely translates along its axis X-X′. Alternatively, the skirt 4 can also be blocked in translation. An example support is a column, inside which the skirt 4 is received. To assemble the skirt 4, the multiaxial robot brings the fixed member 2 into a configuration in which each pin 26a and 26b is across from a corresponding notch 42a and 42b and performs a rotational movement around the central axis X-X′ to engage each of the pins 26a and 26b inside the corresponding notch. More specifically, the relative movement between the guiding element 4 and the fixed member 2 is both a translational movement along the central axis X-X′ and a rotational movement around the central axis X-X′.
To disassemble the skirt 4 from the stator 2 of the turbine manually, the air guiding element 4 and the fixed member 2 should be oriented relative to one another around the central axis X-X′ until reaching a position in which the magnetic attraction means 6 no longer cooperates with the ferromagnetic part 8.
More specifically, the skirt 4 is pivoted around the axis X-X′ in order to move the pins 22a and 22b in a direction opposite the bottom of the notches 42a and 42b. This makes it possible to skew the ferromagnetic parts 8 and the magnets 6: the magnets 6 are no longer radially opposite the parts 8. The magnetic attraction force between the magnets 6 and the ferromagnetic parts 8 is thus reduced.
This operation can thus be done automatically, as outlined below.
The multiaxial robot brings the sprayer 1, then mounted at the end of the arm of the robot, onto a support configured to prevent the skirt 4 from rotating around its axis X-X′. On the support, the skirt 4 nevertheless remains freely translating along the axis X-X′. Alternatively, the skirt 4 is also immobilized on the support in translation along the axis X-X′. Once the skirt 4 is immobilized in rotation, the robot performs a rotational movement around the central axis X-X′ to free each of the pins 26a and 26b outside the corresponding notch. More specifically, the relative movement between the guiding element 4 immobilized on the support and the fixed member 2 mounted at the end of the arm of the robot is both a translational movement along the central axis X-X′ and a rotational movement around the central axis X-X′. The elements 6 and 8 are then no longer across from one another and there is no longer any magnetic attraction, and the skirt 4 can be cleaned or replaced.
In this embodiment, the skirt 4′ defines one or several notches 42′ that each extend parallel to the central axis X-X′.
The manual assembly of the skirt 4′ on the fixed member is then done simply by orienting the skirt 4′ in a configuration where each notch 42′ is across from a corresponding pin 26′ and axially bringing the skirt 4 and the fixed member closer together. This operation can also be done by the multiaxial robot itself, in which case the robot automatically orients the fixed member in the aforementioned configuration. Once this configuration is reached, the skirt 4 moves automatically, following a translational movement, toward the fixed member under the effect of the magnetic attraction.
To disassemble the skirt 4, a specific tool is used, in particular a clamp, comprising two jaws 100A and 100B. Each of the jaws 100A and 100B comprises at least one bevel 102, in particular two bevels 102 and 104, intended to cooperate with inclined surfaces of the skirt 4′ and the body 3 of the sprayer 1, respectively. Indeed, the jaws 100A and 100B are positioned diametrically opposite around the sprayer 1 and are moved radially toward one another in a space between the skirt 4 and the body 3 of the sprayer 1, as shown by the arrows F1 in
The tool can be manipulated by an operator or an automaton.
As an alternative that is not shown and is applicable to all of the embodiments, the skirt 4 is fastened directly on the body 3 of the sprayer, by fastening means comparable to those described above. In this case, the turbine does not include independent circuits 28. The compressed air then for example circulates in channels arranged between the skirt 4 and the stator 2 of the turbine.
According to another alternative that is not illustrated, each magnet 6 is supported by the skirt 4, while each ferromagnetic part 8 is supported by the stator of the turbine 2 or by the body of the sprayer 3, depending on the embodiment in question.
According to another alternative that is not shown, the skirt 4 or the stator 2 is made from a ferromagnetic material, in particular a non-magnetized ferromagnetic alloy.
According to another alternative that is not shown, the pin(s) 26a, 26b belong to the skirt 4 and protrude radially inward. In this case, slots are defined on the outer radial surface of the stator 2 or on the outer radial surface of the body 3 of the sprayer 1 of the turbine, depending on the considered embodiment. These are called positioning ramps. The slots can extend in any direction, in particular in the directions described above relative to the notches 42a and 42b. In the case of helical slots, these slots each have a left pitch or a right pitch around the axis X-X′.
According to another alternative that is not shown, a ring is mounted rotatably around the part with a narrower diameter of the stator 2 of the turbine. Advantageously, this ring includes several magnets distributed with alternating polarities along a peripheral direction around the central axis of the ring. The ring therefore does not exert the same magnetic effect irrespective of its angular position. Indeed, depending on the angular position of the ring, it may either attract ferromagnetic elements, or repel them. In configuration of the skirt 4 mounted on the body 2, it suffices to pivot the ring around the body 2 to push the skirt 4 back from the body 2, which facilitates the disassembly of the skirt 4.
According to another alternative that is not shown, the skirt 4 comprises an outer housing, for example in the form of a blind hole, to receive the lug of a pin wrench. This pin wrench then makes it possible to rotate the skirt 4 around the central axis X-X′ until reaching a position in which the magnetic attraction means 6 no longer cooperates with the ferromagnetic part 8. This wrench comprises a handle that is extended by a semicircular hook bearing the lug and adapted to the outer diameter of the skirt 4.
According to another alternative, the disassembly of the skirt 4 can be done using a strap wrench.
According to another alternative that is not shown, the magnetic attraction means is an electromagnet. In this case, the disassembly of the skirt 4 is made easier because the electromagnet can be deactivated by cutting its power supply.
The technical features of the embodiment and alternatives considered above may be combined with one another to create new embodiments of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1652390 | Mar 2016 | FR | national |
