EP0723817B1 - Booth for treating workpieces by spraying - Google Patents

Description

The subject of the present invention is a treatment of parts by spraying, in particular enameling of ceramic pieces.

Particularly in the sanitary industry, parts made of ceramic are molded then they are covered by spraying a layer of enamel before firing which ensures the transformation of ceramic by giving it mechanical strength properties sufficient for their functions. In addition, this cooking causes a fusion of enamel with self-leveling and the appearance of colors generated by the pigments contained in said enamel layer.

Currently, the piece is arranged in a spray equipped in its center with a spinner, that is to say a plate rotatably mounted about its vertical axis central, designed to receive the part. The cabin spray includes a front opening allowing the forward / backward transfer of parts. An operator, outside of the cabin, operates a gun supplied with enamel in the form thick slip and projects this enamel towards the part which is manually rotated to allow access to all sides, thanks to the spinner.

The enamel is deposited in a layer as regular as possible by the operator, especially avoiding the presence of missing.

The enamel is diluted with water so that it is absorbed by the ceramic, almost instantly, freezing then the enamel layer.

The operator removes the prepared part from the spinner after translating it to him and disposing of this enamelled piece on a transfer cart.

This spray enameling operation which appears simple, actually generates many problems.

A first difficulty lies in loading and unloading parts that require an offset of the operator to access the spinner, even if an assembly on slides makes it possible to improve these loading-unloading, because the parts are heavy for the most part.

Similarly, the manual rotation of the spinner, in addition operator movements to access all surfaces to be glazed, leads to physical problems not negligible.

You should also know that enamel in the form sprayed is harmful to operators and is necessary to comply with very strict regulations in matter that define numbers of particles / unit of air volume.

Also the operators are, most of the time, reduced wearing a dust mask, which is always a constraint strongly detrimental to comfort.

We also understand that the projected and not deposited enamel on the part accumulates on the internal wall of the cabin for a large part and that this enamel is recovered by gravity, for recycling, in a removable container arranged in the bottom of the cabin.

The projected part including the light particles is sucked in by high-power groups equipped with filters. We note that the volumes sucked are very important and that the mass of enamel recovered is no less important. Unlike the bin, which is a simple and easy to collect, cleaning group filters is longer and more complex. Investment for the treatment of the environment is very heavy and the maintenance of resources remains important.

The subject of the present invention is a spray treatment of parts to avoid any exit particles of the product sprayed through the front opening, beyond the standards in force, which allows loading and unloading easier, which leaves time to rest part which has just been treated, which ensures controlled rotation of the part, which remains simple with a reduced maintenance, which promotes recovery by gravity enamel and therefore reduces the amount of product filtered, and which retains the possibility for the operator to set up uses its know-how under ergonomic conditions improved.

For this purpose, the spray booth according to the invention, of a product on a part in particular of a enamel slip on a green ceramic piece, comprising a front wall provided with an opening to allow access to the room using a spray gun operator-held spray, one rear wall, two right and left side walls, a spinner supporting the room is characterized in that it includes a wall curved rear, means for emitting an air curtain at the opening right and side suction means arranged substantially at the corner of the side walls and the front wall.

According to a preferred embodiment, the means emission of an air curtain are arranged in the upper part and opening.

According to another characteristic of the invention, the cabin includes a central base with a motorization for rotary drive, with at least two arms, the ends of which each support a spinner, the central base being placed in the immediate vicinity of said cabin and the length of the arms being such that the spinner passes substantially through the center of the cabin, as well as a door for the passage of arms and turners.

More particularly, the training means in rotation of the single spinner in place in the cabin are integrated into the central base.

These rotary drive means include a drive arm movable in rotation relative to one of its ends around an axis, a motor and a first set of pulleys and a belt, one of the pulleys being driven in rotation by the motor shaft, a roller notched integral with the other pulley and a second set of pulleys, one being integral with the spinner shaft, and a notched belt on the outside and designed to cooperate with the notched roller in a first position of the training arm and designed to let the arm pass in a second position during rotational movements from the central base.

The drive arm includes an actuator.

According to an improvement intended to improve ergonomics, means of adjustment are provided translation of the position of the central base relative to the operator.

According to an improvement of the invention, an apron retractable on the front face is intended to reduce the dimensions of the opening in working position and for let the arm and the spinner pass during the movements of the central base.

In order to improve ergonomics, the height of the tree of each spinner is adapted according to the size of the user.

• la figure 1 montre une cabine selon l'invention, schématiquement représentée, vue de dessus,
• la figure 2 montre une vue de face de la cabine de la figure 1, avec arrachement partiel,
• la figure 3 montre une vue en élévation latérale selon la flèche 3 de la figure 1, en coupe partielle,
• la figure 4 montre une vue de l'entraínement de la tournette lorsqu'elle est positionnée à l'intérieur de la cabine, et
• la figure 5 montre une vue en coupe par un plan vertical suivant la ligne 5-5 de la figure 4.

In order to highlight all the advantages provided by said cabin and so as to better show all the technical characteristics of the invention, there is described below a preferred embodiment which can be found in the accompanying drawings in which :

• FIG. 1 shows a cabin according to the invention, schematically represented, seen from above,
• FIG. 2 shows a front view of the cabin of FIG. 1, with partial cutaway,
• FIG. 3 shows a side elevation view according to arrow 3 in FIG. 1, in partial section,
• FIG. 4 shows a view of the drive of the spinner when it is positioned inside the cabin, and
• FIG. 5 shows a sectional view through a vertical plane along line 5-5 of FIG. 4.

In FIGS. 1, 2 and 3, the cabin 10 is referenced and the means 12 for transferring the parts.

The cabin 10 includes a front wall 14, a wall rear 16 curve with generators oriented vertically as well as two right side walls 18 and left 20 when standing in front of the front wall.

A ceiling 22 closes off the upper part of the cabin and receives a nozzle 24 of the ventilation means not shown, of the suction / filtration type sold in the trade under the trade name HERDING.

In the lower part, the front, side and rear combine to form a hopper 26 of which the opening opens into a recovery tank 28, removable.

The entire cabin rests on feet 30 forming frame.

The right side wall 18 includes a cabinet command 32.

The left side wall 20 comprises means for adjustment 34 in translation of the transfer means 12 of parts, with an adjustment wheel 35 which allows to move away or to bring the transfer means closer to the operator and especially the piece they wear. In Figure 1, the double arrow indicates the direction of this translational movement forward / backward relative to the operator.

The rear wall 16 is equipped with a door 36, mounted pivoting about an axis 38, vertical, passing through the center curvature of the rear wall.

The door is supported by radiating arms 40. These radiating arms are arranged in the upper and lower parts of the cabin.

The door pivots inside the curved rear wall with the necessary games, parallel to this one.

Two high 42 and low 44 transverse beams ensure the mechanical rigidity of the assembly, while a jack pneumatic 43 allows the operation of said door.

The front wall 14 laterally comprises means lighting 46.

An opening 48 is formed on this front wall and in the upper and lower parts, this opening is equipped with compressed air blowing ramps 50 forming an air curtain with an orientation towards the interior of the cabin following a angle symbolized by the arrows 52.

Such ramps are sold for example in the trade under the name "Transvector".

Laterally, there are provided aspirations 54 connected to the stitching 24 of the ventilation means. These aspirations 54 are arranged in the immediate vicinity of the front wall, juxtaposed with the lighting means 46 arranged in the angles.

The air flow circulation in the cabin is symbolized by arrow 56, and the interest of this circulation will appear more specifically during the description of operation below.

The transfer means 12 for the parts are shown in detail in Figures 4 and 5 and schematically in the Figure 1 in particular.

These transfer means 12 include a base control unit 58 with integrated motorization, mounted at rotation, supporting in the example shown three arms 60 arranged at 120 °, radiantly.

The central base is located in the immediate vicinity of the left side wall and the length of the arms is such that their ends pass substantially at the center of the cabin. The central base 58 is connected, as indicated previously, to the translational adjustment means 34.

Each arm is equipped, at its end, with a whirl 62, that is to say a plate mounted for rotation.

It is also planned, in addition to the motorization of the central base, rotational drive means 64 of the spinner on itself.

These rotation drive means 64 of the spinner include a fixed frame 66 relative to the central base and arranged inside this base, supporting an arm drive 68 movable in rotation about an axis 70, movement symbolized by the double arrow 72.

A toothed pulley 74 is mounted on the fixed frame 66.

The drive arm 68 includes a toothed pulley 76. A belt 78 is stretched between the toothed pulleys 74 and 76. The pulley 74 is integral with the drive shaft 80 of an engine 82.

A notched roller 84 is mounted integral and coaxial on the pulley 76 by a connecting screw 86.

The operation of the arm 68 is obtained by a jack 88 whose the piston 90 moves in translation in one direction and in the other according to arrow 92.

Each arm comprises two pulleys 94, 96 of which one 94 is located in the immediate vicinity of the notched roller 84, and the other 96 is integral with the drive shaft 98 of the spinner carried by the arm. Note that this drive shaft 98 has a cradle adapted to the room and its height will be depending on the size of the operator in order to offer a good ergonomics.

An external toothed belt 100 provides the connection between the two pulleys 94 and 96. The teeth are provided for cooperate with the teeth of the notched roller 84.

All of the drive means 64 are positioned so as to drive the spinner when the arm is located in the cab, in the working position, loaded with a part shown in phantom in Figure 2 alone, so as not to not detract from the clarity of the other figures, and referenced to tracking purposes 102.

The operation of such a cabin is now described. The operator loads a piece 102 of ceramic, called green because it has not undergone any cooking, on the spinner 62 in position A in Figure 1.

The operator moves and operates on the control cabinet controls the base rotation switch central 58, which moves the part from position A to position B, without risk for the operator who is outside of the field of rotation of the arms 60. In parallel, the jack 43 opened door 36 to let arm 60 and the spinner 62, which is integral therewith, the assembly moves from position B to position C.

The general switch of the installation ensures, during commissioning of the cabin, lighting 46, commissioning route of the suction unit, and the supply of the ramps 50 compressed air supply.

The operator can then stand in front of the wall front and, using a spray gun type known, it deposits a thick layer of enamel slip. At gradually, it activates, for example using a foot switch, the drive means of the spinner. When the arm is in place in the cabin, the notched roller 84 is brought into contact with the belt 100 notched on the outside by the actuation of the jack 88, the piston of which projects. Motor 82 is switched on works by said foot switch, which rotates the pulley 74 which drives the belt 78, rotates the pulley 76 and therefore the notched roller 84 which is integral therewith.

The belt 100 is in turn rotated, which rotates the part supported by the spinner.

The operator acting on the adjustment wheel 35 approach or move the part away to work with good ergonomic position. This setting is usually made only once at the start of the series of parts identical to process, depending on the dimensions.

It is noted, throughout the spraying phase, that particles that are not deposited on the part, are projected towards the bottom of the cabin and settle on the back wall for larger ones.

The finer particles also settle because the flow air generated by the ramps is found to have zero speed along the curved wall, which facilitates deposition by gravity.

The air flow then picks up a little speed along from the side walls to the aspirations 54, under the effect of depression.

We can notice that the operator in front of the opening 48 is out of the particle circulation, so the density to which it is subjected remains lower than that of the standard setting the maximum level at 1 ppm.

Once the part is finished, the operator loads a new green product on the spindle of position A then appears in front of the control panel to set up rotation of the central base 58 so that the finished part goes from B to C and the new part to be treated from A to B.

In C, the enamelled piece "dries" in the sense that the porous ceramic absorbs water from the enamel slip the deposited layer.

The operator then processes the second part of the same way as before. Once finished, the operator makes again turn the central base, after loading the spinner in A.

The cycle ends with the treatment of the third room.

In subsequent cycles, the operator will need to remove the "dried" part before loading a green product. The semi-continuous operation is initiated.

In order to reduce the dimensions of the opening 48 and avoid any return of particles, it is possible, according to a improvement of the invention, to have an apron retractable at the bottom, which is moved when each movement in rotation of the central base in order to let pass arm and spinner.

In addition, we see that most of the enamel is collected by the bin 28 in the lower part, thanks to the hopper 26.

The arrangement and the curved shape of the rear wall y are for many. Indeed, large particles accumulate on the wall in a sufficiently thick layer so that it does not dry and the adhesion is minimal on the wall. For this purpose, the door must slide in front of the rear wall with sufficient clearance to allow it to remain the thickness of enamel required.

According to another improvement of the invention, the turntables are equipped with any suitable means to ensure rotation blocking of the shaft 98, of one or the other of the pulleys 94 or 96, or the belt 100. It is advisable indeed to immobilize the part while the central base is in motion.

According to a further improvement, the acceleration and the deceleration of the rotation of the central base will be made progressive by adapted steering of the motorization of the transfer means.

Claims (9)

1. Booth for spraying a product onto a workpiece (102), notably an enamel slip onto an unfired ceramic workpiece, comprising a front wall (14) provided with an opening (48) designed to allow access to the workpiece by means of a spray gun held by an operator, a rear wall (16), two side walls, right-hand (18) and left-hand (20), and a turntable (62) supporting the workpiece, characterised in that it comprises a curved rear wall (16), means (50) for emitting an air curtain in line with the opening (48) and lateral suction means (54) disposed substantially at the corners of the side walls and front wall.
2. Booth according to Claim 1, characterised in that the means (50) of emitting an air curtain are disposed at the top and bottom part of the opening (48).
3. Booth according to Claim 1 or 2, characterised in that it comprises a central base (58) with a drive for driving in rotation having at least two arms (60) whose ends each support a turntable (62), the central base (58) being disposed in the immediate vicinity of said booth and the length of the arms being such that the turntable (62) passes substantially through the centre of the booth, and a door (36) for the arms (60) and turntables (62) to pass.
4. Booth according to Claim 3, characterised in that it comprises means (64) for rotating the only turntable (62) in position in the booth, integrated into the central base.
5. Booth according to Claim 4, characterised in that the rotation means (64) comprise a drive arm (68) able to move in rotation with respect to one of its ends about a shaft (70), a motor (82) and a first set of pulleys (74, 76) and a belt (78), one (74) of the pulleys being rotated by the shaft (80) of the motor (82), a notched wheel (84) fixed to the other pulley (76) and a second set of pulleys (94, 96), one (96) being fixed to the shaft (98) of the turntable, and a belt (100) notched on the outside and designed to cooperate with the notched wheel (84) in a first position of the drive arm (68) and designed to allow the arm (60) to pass in a second position during the rotation movements of the central base.
6. Booth according to Claim 5, characterised in that the drive arm (68) comprises an operating jack (88).
7. Booth according to any one of Claims 3 to 6, characterised in that it comprises means (34) for the front/rear translational adjustment of the central base with respect to the operator.
8. Booth according to any one of Claims 3 to 7, characterised in that it comprises a retractable apron on the front face designed to reduce the dimensions of the opening in the working position and to allow the arm (60) and turntable (62) to pass during movements of the central base (58).
9. Booth according to any one of the preceding claims, characterised in that the drive shaft (98) of each turntable carries a workpiece support cradle and the height of this drive shaft is adapted ergonomically according to the size of the operator.

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