FR2464102A1 - PROCESS AND APPARATUS FOR SPRAY PAINTING THE INTERNAL SURFACE OF CLOSED BOTTOM TUBULAR CONTAINERS, SUCH AS METALLIC BOXES, WITH SUBSTANTIALLY AXIAL CONTAINER ROTATION - Google Patents

Abstract

A PLURALITY OF SPINDLES 6 DRIVEN AT A ROTATION SPEED SET BY A MOTOR 35 DOORS CLAMPING PLATES SUITABLE TO FIX MAGNETIC OR PNEUMATICALLY THE CONCAVE BOTTOM OF BOXES 16. THESE SPINDLES 6 CAN BE LOWERED THROUGH ORIFICES OF ' A PLATE 11 FOR THE INTERIOR PAINTING OF THE BOXES 16 BY SPRAY NOZZLES 25. TABLE 11 IS EQUIPPED WITH BRAKING MEANS FOR THE BOXES 16 IN THE END OF THE PAINTING PROCESS POSITION, AFTER WHICH THE BOX IS MOVED LATERAL UNDER THE ACTION OF THE BOXES. RESIDUAL ROTATION FORCES. APPLICATION: PAINT WITH CANS GUN.

Description

The invention relates to a method and an apparatus for

  spray painting of closed containers at the bottom, in parti-

  of metal cans, in which the box is

  by its open end on an integral spray nozzle

  solidly fixed to the frame and is rotated, after which the box is rotated axially over the inner spray nozzle, or painted internally

and we evacuate it.

  Apparatus suitable for carrying out such a method are known. In general, they comprise a device for bringing the boxes one by one to a position of

  waiting. This feeding device can be in the form of

  the screw or conveyor. In addition, a device

  As for the box with adhesion is expected to accelerate the

  box and drive it around its axis at a rotating speed.

  predetermined setpoint. Acceleration and training

  eccentric weight boxes, in two parts and stamped poses significant problems, in particular

  when they are already decorated externally by

  paint-free or anti-ultraviolet paints

  purples. For an economic mode of work, it is desirable that the speed of rotation is 3500 revolutions / min. This is particularly the case for painting processes in which

  relative movement is expected between the spray system

  and the box, in the direction of the axis of the box. In

  so-called stationary spraying systems, where the

  are only rotated during the spraying process, rotation speeds of

RPM is still needed.

  In both known methods, the radial velocity of the

  boxes is caused by pressure contact between the

  king of the box and a rubbing roller. So that the rou-

  the water of friction can exert on the circumference of the

  sufficient pressure for sufficient acceleration

  The device has four to six roller bearings

  counterpressure or guidance that must be

  at the same time. This means that with each process of pul-

  internal verification, it is necessary to accelerate the speed of con-

  sign not only the weight of the box, for example 33 g,

  but besides the weight of all the rolls of counter-pres-

  and parts thereof, the mass of which represents 2 to

  3 times that of the box. The situation is made more dif-

  This is because between the drive elements and the circumference of the box, only a relatively small skirt should occur. This is desirable on the one hand to protect the exterior decoration but it is still

  necessary to use for exterior decoration paints

  tures or varnish of high mechanical strength. But a weak

  skating would also be desirable from the point of view of

  painting. Indeed, if a skating occurs, it

  must exaggerate the amount of paint to get a coating-

  completely coherent despite skating.

  Another significant difficulty that the device for accelerating and driving the box of known paint systems lies in the fact that for these devices

  the box must be rolled on its free edge.

  This rolled edge has firstly role to make more rigid and more resistant the side wall of the box, vis-à-vis the friction forces and acceleration that occur. But

  the rolled edge also has the function of stabilizing the posi-

  tion of the box within the drive device because at high speeds of rotation, the eccentric bottom

  weight gives the box a tendency to escape laterally.

  Since the rolled edge must also be painted,

  that the interior spray nozzle still has to spray paint in positions outside the

  box so that a reliable painting of the rolled edge is guaranteed.

  The result is a series of additional measures aimed at

  collect the paint, clean the machine parts

  viriant and protect people against paint fumes. Paint consumption can also be increased

  these conditions by up to about 10%.

  This extra consumption of paint does not serve to paint the boxes, but then, painfully, remove parts of the machine. Volatile fractions must be destroyed using after-burners. In addition, the known devices include the aforementioned nozzle used for the interior painting of the box and

  which is advantageously fixed disposition. In addition, a

  Positive drive can be expected to move axially-

  the rotating box relative to the nozzle. In addition, control and distribution devices are usually provided for controlling the apparatus and devices

according to a prescribed work cycle.

  The object of the invention is to improve a method and an apparatus of the species defined more precisely above, of

  in such a way that the difficulties indicated can be

  to a large extent. In particular, the

  box itself and its exterior decoration are spared.

  In addition, it is a question of limiting to the quantity necessary the consumption of paint for the interior painting. Another goal is to be able to perform interior painting without the box must have a rolled edge. Finally, the

  provision can be built with less labor

and technical means.

  According to the invention, this problem is solved by the fact that by means of a spindle, a planar holding surface is constantly driven at the set rotation speed, while simultaneously generating a magnetic or pneumatic retaining force, this retaining surface is moved against an annular surface of the bottom of the rotating box and that one

  accelerates the box abruptly, with axial drive, jus-

  only at the set rotation speed, with a skating

  less than 10 mm, preferably less than 5 mm.

  In clamping chucks, including for boxes, it

  It is known to use at the same time

  gnetic or pneumatic. Thus, the German utility model

  No. 6,752,437 shows an apparatus for painting or electrostatically spraying a hollow body. The hollow body hanging freely downward is carried by a sucker, the sucker

  applying to the closed bottom of the container. The suction cup itself

  relies on a conveyor chain. This is a static inner liner because neither the box nor the suction cup are rotated. We therefore do not encounter the problems that are posed in particular, as we

  explained above, by the need to speed up and

  246410t2 drag the box up to a rotation speed of 1000 to

3500 rpm and more.

  It is known, moreover, to trim the ends or-

  boxes, to provide a mandrel for

  rabies that does not apply only to the bottom but also encloses the body of the box in its regions close to the bottom, the cutting head mechanically engaging and guiding in the open end of the box and pushing it against the chuck, the chuck and the cutting device being driven. Here again, the chuck

  may be equipped with a pneumatic device to increase

  the force of the chuck and facilitate the ejection of the chopped box (see DE-OS 2,456,097). In this known apparatus, the

  box is supported and mechanically clamped at both ends.

  mitiated and driven by both ends.

  This is not possible in the case of

  laughter because here, it is necessary that the end of the box and all the inside of the wall of the box remain free for the process of coating. It is for this reason that for

  interior painting machines, we use almost exclusively

  However, frictional drive by the outer sidewall is a good practice, although the friction drive causes a risk of damage to the exterior decoration. It should be added that the trimming of the box is carried out immediately

  after stamping, so before the box carries a

  external coration. In addition, the relative movements between box and chuck play no role. You can also, with the chucks, accelerate the box from the stop. The invention is based on this surprising idea that for the interior painting of a box closed at one end, one

  can accelerate and drag this one almost

  starting from standstill at the nomi-

  from 1000 to more than 3500 rpm, without significant slippage, only by the more stable bottom side of the box, so that the drive does not cause any deformation of the

  box nor any damage to the exterior decoration. The entrainment

  By the bottom side only, it is also possible to carry out the interior painting without providing the body of the box with a rim or a rolled edge. Surprisingly, it appeared that starting from the complete stop, one can accelerate the box, during a continuous and uniform movement, not only in

  circumferential direction but also axially

  the. Slippage that occurs even at rotational speeds

  3500 rpm, is very much less than 10 mm, measured

  the clamping surface and the annular surface located towards the bottom, which comes into contact with the clamping surface. Clamping can be ensured by permanent magnets or by

  an aspiration of air. It emerged that despite the uni-

  side of the box, these clamping forces are entirely sufficient to safely accelerate the box in the centered position and even to maintain it surely centered vis-à-vis

  displacement forces from the nozzle. A particular advantage

  particular is that not only can the acceleration

  training and training only from the bottom side in

  swimming as much as possible the wall and the exterior decoration,

  but that in addition, then braking the box, we can ap-

  simply bend braking forces by the bottom and more precisely so that under the sole action of the residual forces of rotation, the box, away from the surface

  tightening, automatically moves laterally from its po-

  sition aligned with the axis of rotation and thus, through an evacuation table surface, it can be brought to 1 '

  one of the known evacuation devices without this

  site of additional transport, training and

  or deviation of a particular nature. Thanks to that too, the device is significantly simplified. We can limit the quantity of paint to that which is necessary because there is no rolled edge and that consequently, no measurement is

  necessary either to paint the rolled edge. This simplifies

  also the devices used to collect and suck

  excess paint and solvent vapors.

  The following invention will be explained more precisely with reference to an exemplary embodiment represented by the schematic drawings in which: FIG. 1 is a simplified vertical section of an apparatus for carrying out the method according to FIG. invention; - Figure 2 is a vertical section of a detail to more

  large scale, the clamping surface being provided with a

  which generates magnetic retaining forces and - Figure 3 is a detail in vertical section of a

  example of modified execution of the parts located in the

area of the clamping surface.

  The apparatus shown in FIG.

  sis 1 integral with the frame. This one presents, on two parts

  vertical frame, two sections of slide 2 on the-

  sliding sliding bearings 4 of a table or part of frame 3 directed horizontally. The table or

  part of frame 3 has at spaced points

  vertical perforations through which a spindle passes 6. This is rotatably mounted by means of bearings 5 on the frame part 3 and fixed in the direction

  axial to them by rods or similar elements.

  8. The spindle 6 can be rotated in its

  5 in the direction of the arrow 7.

  On pin 6 is wedged firmly, at its end si-

  below the chassis portion 3, a toothed wheel 9 surrounded by a driving element, in particular a toothed belt 10. As indicated by the broken lines 6 in FIG. 1, several of these pins 6 are mounted in

  the chassis part 3. Each spindle has a wheel den-

  9. The toothed belt 10 surrounds all the toothed wheels

  9 as well as the drive gear of a drive motor.

  40, fixed below the chassis part 3. Thus,

  all pins 6 can be rotated simultaneously

  thanks to the drive 9, 10 and 40.

  At the upper end, the spindle 6 carries a clamping plate 13 which, in the example of Figure 2, is screwed firmly to the end end of the spindle 6. The clamping plate 13 has a horizontal clamping surface plane

  14, facing upwards, in which are embedded

  permanent magnets 15 for generating the holding force

desired.

  As shown in FIG. 1, the frame 1 carries, at the

  above the sections of slide 2, a table top 11 which

  present, in the alignment of the pins 6, recesses 12.

  The free width of the recesses 12 is calculated so that

  that the clamping plates 13 can freely pass through

  to the recesses 12 of the table top 11. The top of the table top 11 is equipped, for each recess 12, braking elements 18 arranged in a specific manner and whose role will be explained later. The container that is to paint internally is designated 16. In the example shown, it is a box having the typical section stamped boxes. We see that the box has a cylindrical body devoid of edge

  rolled and which joins, by a frustoconical portion 17a, an over-

  planar annular face delimiting a dome shaped central portion 17. As shown in FIG. 2, the diameter

  of the clamping plate 13 is large enough for the

  Permanent mants 15 are at the level of the annular surface of the bottom. On the other side, the bottom of the clamping plate 13 is small enough that the diameter of the box 16 exceeds the diameter of the clamping plate 13. As a result, as shown in FIG. 2, upon lowering of the spindle 6, when the clamping plate 13 disappears under the table top 11 through the recess 12, it is possible for the frustoconical bottom portion 17a to cooperate with the braking elements 18 integral with the frame so that that the

  box 16 is lifted from the clamping plate 13 and simultaneously

  braked from the high speed of operation. The provision is such that cooperation

  couples acting on the box have the effect of

  the box removed from the clamping plate 13 by leaving it in its position aligned with the axis of rotation 80 of the spindle 6, above the table surface, the box then arriving with appropriate guidance in a housing with a view to evacuation. This process is fully automatic and taking advantage of residual

  the high speed of rotation, in combination with the

  braking forces exerted by the frame and which apply

  in the background area of the box.

  Above the table surface 11 is disposed, in alignment with the axis of rotation 80 of the box, a nozzle of

  spraying 25 communicating through a pipe-soul

  born 26, 27 with a control valve 28 and a source of

  painting. Each spindle 6 is accompanied by a spraying nozzle.

  internalization. The inner spray nozzles are directed downward and radially so that adjacent nozzles 25 may each be provided with a common paint collection device 25a.

  The position of the interior spray nozzle

  to the initial waiting position of a paint box.

  dre 16 is calculated such that after driving the box by the clamping surface 14 which moves towards the baut, the spindle is first raised to a top dead position corresponding to the smaller distance between the inner spray nozzle 25 and the bottom 17, 17a. Only then, through the valve 28, the interior spraying process is triggered so that the bottom of the box is first coated, after which, when the spindle 6 then lowers, the inner surface of the box

  is continuously coated helically from bottom to edge.

  The box is individually fed by known devices such as supply stars or feed screws, through a feed table surface, for example the

  above the table 11, and arrives at a waiting position

  on the axis of rotation 80, the clamping plate 13 and the spindle 6 being below the top of the table top 11. The feed star 20 can be driven constantly at a uniform speed by the spindle. output 34 of a motor 35, via shafts 21, 22 mounted in the frame 1 suitably, for example 30, and via a belt transmission 31, 32, 33. It It must be remembered that for each pin 6 is provided a feed device 20,

  21. The drive of the feeder can also be carried out

  kill intermittently or cyclically.

  The drive motor 35 is provided at the same time,

  in the example shown, to generate a cyclical movement

  than raising and lowering the chassis part 3. At this

  effect, on the underside of the chassis part 3 is ar-

  ticulée, by a universal joint 37, a rod 36 whose trunnion engages, in the example shown, in the groove of an eccentric 38 driven by the motor 35. By acting on the speed of rotation of the motor 35 and on the adjustment or the structure of the eccentric 38, it is easy to precisely adjust the stroke length and the running speed

  of the chassis part and if necessary modify them.

  When the apparatus is operating, the motor 40 used to drive the pins 6 operates constantly and at a fast pace.

  become uniform so that the pins 6 are constantly in

  streaks at the set rotation speed.

  As soon as a box 16 is in standby position aligned with the corresponding axis of rotation, at each station

  the apparatus according to FIG. 1, a cycle is de-

  latch and the frame portion 3 is raised according to the

  double die 41, by way of the eccentric drive.

  38. The clamping plate 13 passes through the recess

  12 of the table top 11 and finally arrives in

  tact with the annular surface of the bottom of the box in posi-

  waiting period. Surprisingly, it has appeared that by this annular surface, the box can be fixed to the clamping surface 14, by means of a suitable power of the magnets

  , surely enough for the stationary box 16 to be able to

  It can only be accelerated abruptly to the set speed without noticeable slippage in the area of the annular surface or the contact surface and without the center position of the box changing. Box 16 as well

  accelerated abruptly is dragged upwards with the

  that of clamping 13 which moves continuously towards the

  up to the top dead center position of pin 6.

  In this region, as already indicated, the painting process begins. It is firstly the bottom of the box which is reliably coated, which is facilitated by the fact that, in the region of the top dead center, despite the uniform rotation of the eccentric 38, the movement of lowering the clamping plate 13 occurs first slowly and

  that it continues in an accelerated manner only after a

  tion of the eccentric 38. Thus, once

  the bottom has been carefully coated, the coating of the

  the box continues in a helix from the bottom to the open end and ends when the un-rolled edge is reached,

  so that small amounts of paint only

  from the box and are collected by the collective

  25a and must be evacuated.

  Tests have shown that instead of the magnetic retaining force, pneumatic force can also be effectively used, the suction force being able to be applied in the region of the clamping surface 14 by a central bore of the spindle 6 Such a pneumatic clamping effect is indicated in the variant of FIG. 3. Here, the spindle 52 has a longitudinal bore 54 which opens, at 55,

  at the top of a field-shaped ejector

  gnon 53 subjected to a spring preload. Here braking

  does not take place by direct application of

  swim in the bottom of the box but indirectly through the

  re of an intermediate member 51, mounted so as to rotate freely, which forms on the one hand the clamping surface of the pin 52 and on the other hand has an outer collar

  which, with corresponding structural surfaces of the

  of the table top 11a forms the braking device

  50. Here again, pin 52 is constantly being driven

  at the set rotation speed. By the pneumatic force

  than the retainer, the spindle, the intermediate member 51, the disc

  Positive ejection 53 and the box are abruptly tightened in

  a block that suddenly takes the speed of rotation of con-

  sign. When the spindle lowers, the intermediate member 51 arrives at the braking position so that the box and 1 '

  intermediate member 51 are braked and raised from the

  clamping face by the ejection device.

  The same apparatus can advantageously be used for painting

  outside-preferably simultaneous-because the box is

  only supported in the area of the bottom surface and

  dragged by it. To the external spray nozzle may be added conventional devices for collecting the excess paint. It can be connected by

  a valve 76 to the piping system 27.

2464102

Claims (5)

R E V E N D I C A T I 0 N S   1. A method for spray painting containers closed at the bottom, in particular metal boxes, wherein the box (16) is aligned by its open end on an inner spray nozzle (25) integral with the frame (1) and puts it in rotation, after which we move axially   the box (16) rotating over the spraying nozzle (25)   interior painting, painting it internally and   characterized by the fact that by means of a spindle   (6), one constantly drives at the speed of rotation of   sign a flat retaining surface (13), which by generating   simultaneously a magnetic or pneumatic retaining force,   moves this retaining surface (13) against an annular surface   the bottom of the box (16) rotating and accelerating   the box abruptly, with axial drive, until the   set rotation speed, with slip   mm, preferably less than 5 mm.   2. Method according to claim 1, characterized in that, the spindle (6) up and down cyclically, the spraying process is triggered when the top dead center of the spindle is reached and the smallest distance between the bottom ( 17) of the box and the nozzle (25) is reached and continues during the lowering movement of the spindle (6). 3. Method according to claim 1 or 2, characterized in that after the end of the spraying process, the gearbox rotating at the target speed is raised from the surface.   plane (16) of the spindle (6) and simultaneously braked by   application of braking forces in the bottom region (17a)   such that under the action of the rotational forces   the box is removed laterally from its on the axis of rotation (80).   4. Apparatus for carrying out the method according to one   Claims 1 to 3, comprising a delivery device   boxes (20) one by one at a waiting position, a dis-   positive (13) applying to the box (16) with adhesion so as to accelerate it and drive it about the axis to a   predetermined set speed, a nozzle (25), in particular   binding intended for the interior painting of the box, a   training device (35,36,38) serving to move relative-   in axial direction the rotating box (16) and the nozzle (25) and control and dispensing devices for controlling the apparatus and devices according to a prescribed operating cycle, characterized in that it comprises at least a vertical spindle (6) which can be constantly driven at the set rotation speed, provided with a flat clamping surface (13) and a device   clamping device to the latter, acting by a magnetic force   (Fig. 2) or by suction (Fig. 3), that the clamping surface (13) can be moved in the direction of the axis of rotation, passing through a waiting position in the feed plane. box, up to a top dead position,   that in this last position can be triggered the   spray and that the downward trajectory of   the spindle is fitted with a braking device (18,51) cooperating   with the bottom of the box (16) rotating so that the box can be removed from the clamping surface (13)   and be braked so as to move automatically   with rotation, on the evacuation plan, under the   rotation residual forces.   5. Apparatus according to claim 4, characterized by   several pins (6) are mounted so as to be able to   see rotating freely without being able to move axially in a common sliding frame (3) which can be raised and lowered, which carries a common rotation drive (10) to all the pins (6) and which can be raised and s' lower   cyclically relative to the spray nozzles (25)   the supply and evacuation plans and the provisions   braking arms, by means of crank arms (38) or   eccentric that can be changed or adjusted.