US 3906894 A
A process and apparatus are provided for spray coating an annular race or seam on a motor vehicle wheel or the like. The apparatus includes a spraying device and a conveyor carrying a frame for supporting the wheel in a vertical position; the spraying device has a first carriage adapted to engage and move horizontally with the frame, a second carriage supported by the first carriage adapted to move towards and from the frame and a third carriage supported by the second carriage and adapted to move vertically therefrom; the third carriage being a spray head and carrying rollers adapted to remove the wheel from its support on the frame and to rotate it in front of the spray head.
Description (OCR text may contain errors)
United States Patent 1191 1111 3,906,894 Pesapane 1 Sept. 23, 1975 [5 APPARATUS ADAPTED FOR THE 2,727,979 4/1957 Verba et al. 118/321 x PROTECTIVE COATING OF THE RACE 3,606,162 9/1971 Lehmann 1 18/323 X Appl. No.: 345,445
Foreign Application Priority Data Mar. 31, 1972 Italy 22703/72 US. Cl. 118/315; 118/321; 118/322 Int. Cl. B05C 5/00; BOSC 13/02 Field of Search 118/323, 321, 500, 308,
References Cited UNITED STATES PATENTS 3/1955 Ransburg 118/323 X Primary Examiner-.lohn P, McIntosh Attorney, Agent, or Firm stevens, Davis, Miller & Mosher  ABSTRACT A process and apparatus are provided for spray coating an annular race or seam on a motor vehicle wheel or the like. The apparatus includes a spraying device and a conveyor carrying a frame for supporting the wheel in a vertical position; the spraying device has a first carriage adapted to engage and move horizontally with the frame, a second carriage supported by the first carriage adapted to move towards and from the frame and a third carriage supported by the second carriage and adapted to move vertically therefrom; the third carriage being a spray head and carrying rollers adapted to remove the wheel from its support on the frame and to rotate it in front of the spray head.
7 Claims, 7 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of3 3,906,894
6 .4 I J A44; H M 2 4 FIG. 2
US Patent Sept. 23,1975 shw 2 of3 3,906,894
US Patent Sept. 23,1975 Sheet 3 on 3,906,894
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APPARATUS ADAPTED FOR THE PROTECTIVE COATING OF THE RACE BETWEEN THE RIM AND DISC OF MOTORVEHICLE WHEELS The present invention relates to apparatus for the protective coating or for the filling with powder resins, varnishes or metal coating, of annular cavities or seam that form between the rims and wheel discs of motor car wheels after their assembly. More particularly, the apparatus provided by the invention is adapted to be used for coating a wheel or the like with any kind of synthetic resin, either in the form of a powder or dispersed in a liquid medium, powdery or liquid paints, or of any other types of metal coating. The synthetic resin may be a thermoplastic or thermosetting resin.
Until quite recently, the protective coating of wheels was exclusively carried out by means of conventional painting or coating processes (i.e.: electrophoresis, manual or automatic electrostatic coating, etc.). Such processes used resins dissolved or dispersed in solvents.
Recently, the motor car manufacturers, looking for wheel coating processes that would insure better results, have turned their attention to coating processes which use resin powders.
The resin powders, as is known, are applied by means of different systems, such as, for instance, in a normal fluid bed or in an electrostatic bed, by electrostatic spraying, etc. Among all of these systems, the one that is best suited for the coating of wheels, because of its technical and economical conditions, is the electrostatic spray coating system. Electrostatic spraying produces thin thicknesses (less than 100 microns) and is adapted for use as a part of a large production line.
It has been found, however, that electrostatic spraying is not completely satisfactory for coating motor car wheels. One problem is that it is desirable to transfer the wheels across the plant in a vertical position on wheel carrying frames fixed to an aerial conveyor chain. Such carrier frames should carry at least two or three wheels each. In this way it is possible to keep the speed of the production line within reasonable limits and therefore avoid excessive lengths. With the wheels in a horizontal position it is not possible to load more than one wheel per frame, since the frame would be rather complicated and make loading of the wheels very difficult because of the shape of the wheel.
Another problem is that the seam or joint formed on the face of the wheel when the wheel disc is joined with the rim must be completely coated or preferably filled with resin to avoid rusting or corrosion from starting at the joint. Experience has shown that this second problem is not solved by merely disposing the wheels in a vertical position. Moreover, with the heretofore available electrostatic spray process it is not possible to sufficiently cover up the wheel seam or race and cavities hidden from the electrostatic field unless the delivery rate of the spray-nozzles is increased to the point where the mechanical action of the powder jet becomes of preponderant importance. Moreover, in this way, too much powder is deposited on the wheel without materially improving the coating of the race or seam formed by the joining of the wheel disc with the rim. Also, due to the vertical position of the wheel, powder accumulates because of gravity at the bottom of the wheel.
Thus, the conventional electrostatic systems have the disadvantage that the race is inadequately protected,
consumption of the coating powder is high and the coating does not have a uniform thickness.
Because of these disadvantages it has been the practice commercially to coat motor car wheels while they are supported in a horizontal position with only one wheel per hook. Prior attempts to avoid the problems of painting vertically hanging wheels have been unsuccessful. 7
An object of this invention is, therefore, to provide an apparatus for coating or filling annular grooves, or seams of bodies capable of being coated with paints or the like, particularly the annular seams existing on the outer face of motor car wheels, which is devoid of all the disadvantages of the heretofore coating systems. Another object of the invention is to provide apparatus for coating motor vehicle wheels or the like which will satisfactorily coat or fill the annular groove formed at the seam between the rim and wheel disc without producing a non-uniform coating on the wheel.
Still another object of this invention is to provide an apparatus that will allow the coating of the annular cavity of several pieces or wheels simultaneously without changing the normal continuous production rate of the wheels or of other bodies having annular cavities to be coated or to be filled.
Yet another object of the invention is to provide a special apparatus movable between two fixed points that is suited for performing the coating process in a continuous way regardless of the type of resin or paint or metal coat required for the coating.
All these objects and others which will become apparent from the following description are achieved by providing a process for coating annular races or cavities of motor wheels or the like with powdered resins, paints, metal coatings and the like, wherein the wheels are preheated while disposed on a frame which supports the wheels in a non-rotating vertical position, the wheels are lifted from their supports and disposed on rollers which rotate them about their axis, the rotating wheels are sprayed with powdered resin, paint or the like until the annular race or seam of each wheel is coated, the wheels are returned to their nonrotating supports and permitted to cool or they are passed through a forced air cooling tunnel. A single frame may support one or a plurality of wheels one above the other with all of the wheels being disposed in a vertical plane.
In particular, the apparatus of the invention provides for the application of the resin on the heated wheel so that the resin, either thermoplastic or thermosetting, will melt upon contact with the metal surface and while in the liquid state will enter the seam existing between the rim and disc.
Capillarity phenomena favors penetration of the resin into the seam.
The pre-heating may be carried out in a special oven, which may possibly coincide with the drying oven after the surface pre-treatment of the body, in such a way that the wheel arrives at the coating machine at a temperature of between and C. The temperature of the wheel may be varied, however, depending upon the melting point of the resin.
The heated wheels are coated with a fixed powder spraying nozzle and the wheel or body is revolved about its axis while being sprayed. Rotation of the wheel during spraying insures the exact positioning of the nozzle with respect to all the points of the seam to be coated.
The same effect would not be obtained, obviously, if
the wheel were stationary and the spraying head were madeto revolve since the unavoidable constructional variations betweenone frame to the other would involve the non-concentricity of the seam with respect to the circumference on which the spraying head is moved. The success of the process does not depend upon the revolving speed of the wheel. On the contrary, the spraying time determines the thickness of the coating and the extent of its coverage.
Thus, it is advisable to use spraying times of not less than seconds, but of course, the exact time must be established each time by means of practical tests on the resins to be used.
In order to avoid deformation of the jet of powder by air displacements caused by high revolving speeds of the wheel, it is advisable to revolve the wheel body slowly but rapidly enough to insure at least a few complete revolutions of the wheel during the coating time.
The powder, or different coating material, is sprayed through the nozzle with or without air, and the spray rate will depend on the coating time available and on the size of the race to be coated.
In case the coating or filling up of the race must be carried out with liquid paints or with a deposit of metal, it is not necessary to pre-heat the wheel or other body to be coated, but all the other steps of the process remain the same as those previously described.
Obvious'ly, the spraying nozzles will be fitted to the material to be sprayed.
The process described offers several advantages over the heretofore known systems or over those still in the experimental stage.
These advantages are substantially the following:
1 The process permits treating the wheels while they are disposed in a vertical position, that is, with their axis in a horizontal position. Moreover, several wheels may be carried on one wheel-carrying-frame.
2. The process coats or, if required, completely fills the annular race or seam that is formed in the wheel face between the rim and disc of the wheel, thereby completely welding together these two elements.
3. The process reduces the quantity of powder necessary for a complete coating of the wheel.
4. The process deposits uniform coating layers on the wheel; that is, layers with thicknesses which vary little from point to point.
The same advantages will appear in all those cases in which there are annular cavities to be coated, and they will be more evident the larger is the number of annular cavities on the piece to be processed.
In fact, it will be quite evident that this invention is applicable also in the case that the body has several cavities or seams and these same cavities are arranged on more than one face of the piece to be coated. It will suffice, in fact, to locate a plurality of spraying nozzles if all the annular cavities are concentric, and more apparatuses of the type described hereunder if the annular cavities are not concentric.
The practical execution, in a continuous way, of the coating process, of the invention is carried out by means of a special movable spraying device having a special wheel-carrying frame suspended on a conventional aerial conveyor, and of a machine provided with automatic means for the disengagement of the wheels from the frame, for revolving the wheels, spraying powders on the wheels and for repositioning the wheels on the frame. The machine then returns to its starting position ready for another spraying cycle of wheels fixed to the next frame. The speeds of the machine and of the piece-carrying frame are synchronized with the speed of the aerial conveyor which carries the frame.
More particularly, the apparatus provided by the invention hasa frame made of rods, substantially of rectangular shape, connected to an aerial conveyor and provided with means for supporting at least one nonrotating wheel in a vertical position, that is with its axis on a horizontal plane. The apparatus is also provided with means for the temporary locking of the frame itself onto a coating machine. The coating machine is provided with a first carriage which moves along a preestablished run between two fixed supports. The :first carriage travels in a direction parallel with and at the same speed as the frame and the aerial conveyor; a second carriage supported by the first carriage, and provided with means for moving towards the wheelcarrying frame; a third carriage, supported by the second one, vertically displaceable and provided with rollers for rotating the wheels after they are displaced from the frame supports, spraying nozzles for spraying the coating material towards the seams to be coated, means for temporarily hooking up of the frame as well as limiting and controlling means for the preset forward and reversing runs of the carriages.
The apparatus provided by the invention will be more clearly understood from the following detailed description of a preferred but not exclusive practical embodiment thereof with reference to the drawing, wherein:
FIGS. 1 and 2, respectively, represent a schematic front and side view of a wheel-carrying frame according to an embodiment of the invention, suspended from an aerial conveyor;
FIGS. 3 and 4 show, respectively, in a schematical form, a front and side view of the coating machine according to the invention, in the waiting position for receiving the wheel-carrying frame;
FIGS. 5 and 6 show, respectively, in a schematical form, the same machine of FIGS. 3 and 4 in the spraying position, that is, with the wheels coupled to the spraying head; while FIG. 7 shows a detail of the same machine, and more precisely a wheel supported by two revolving rollers.
With reference to these Figures, and more particularly to FIGS. 1 and 2, the wheel-carrying frame 1 has two vertical rods 2 and 2 connected to each other by two bars 3 and 3; to the two vertical rods are fixed two pairs of included rod-like struts 44' and 5-5, two for each vertical rod, which support the two motor car wheels 6 and 7. The annular races to be coated are marked 8 and 8'.
Two or more wheels may be disposed on the same frame in a vertical position one above the other.
The two pairs of struts must be spaced from each other so as to leave free the lower part of the wheel. Each wheel must be placed at a suitable distance from the other.
Frame 1 has on its top a connecting bar 9 connecting the frame with the aerial conveyor 10 and at the lower end of the frame a positioning pin 11. Upper connecting bar 9 serves also as an upper positioning pin.
These two pins 9 and 11 insure the positioning and the locking in place of the wheel-carrying frame on the coating machine that applies the powder coating to the wheel. During this latter operation the machine and the frame must move at speeds which are synchronized with the speed of the aerial conveyor to which the wheel-carrying frame is attached.
The machine, illustrated in FIGS. 3, 4, 5 and 6, has three carriages of which the first supports the other two.
The first carriage 12 is mounted movably, and with a pre-established run on two opposing supporting abutments l3 and 14 whose kinematic motion means, of easy realization, are not represented in the drawing since various different known means may be used; eg slides on rollers driven by pistons or motors.
Carriage 12 effects a traversing movement parallel to and synchronous with aerial conveyor 10, and, thus, with wheel-carrying frame 1. A second carriage 15 is fixed on the mobile section of carriage 12, visible in FIGS. 4 and 6. Carriage 15 carries third carriage 16. The second carriage 15 has a sliding saddle or a telescopic means or the like and is provided with a conventional driving means adapted for moving carriage 15 over a predetermined route towards the wheel-carrying frame, FIG. 6, that is, in a direction transverse to the direction of the travel of frame 1.
The third carriage 16, which, substantially, forms the spraying head for spraying the powder, is mounted onto the free end of carriage l5 and is built in such a way as to be able to be displaced vertically in order to detach the wheels, as will be illustrated further on, from the frame and to revolve them.
For this purpose, as many groups of rollers 17, 17, as there are wheels in the wheel-carrying frame are mounted on carriage 16. Each group of rollers lifts one wheel and has at least two rollers one of which is motor-driven in continuous rotary motion, while the other roller is free-wheeling.
One electric motor or pneumatic driving means (not represented in the drawing) may drive through a belt or a chain transmission all the driven rollers carried by carriage 16.
The rollers 17, 17' of each group are mounted in such a way that with the forward travel of carriage 15 they are brought under the lower part of each wheel (resting on the four struts 44 and 5-5 fixed to the vertical rods 2 and 2 of the frame) and upon the vertical travel of carriage 16 lift each wheel out of its seat.
Carriage 16 carries also forked means 18 and 18' for the positioning and blocking of the piece-carrying frame 1, which forked means act respectively on pins 9 and 11 of the frame 1.
Moreover, nozzles 19 and 19 for the spraying of the coating powder or the coating paint are positioned on carriage 16, perpendicularly to the seat of the race to be coated.
The equipment is completed by a powder (or paint) storage tank 20, which reaches the nozzles through ducts 21 and 22 (see FIG. 4); the spraying means (air or any other means) are of the known type.
In operation, the cycle starts by positioning carriage 12 and thus the whole system of carriages on the feeding side of the machine, that is, on the side of abutment 12. The oncoming frame carried along by the aerial conveyor to its proper position activates a microswitch (not shown) causing the advancing of carriage 15 (second movement) which brings carriage 16 near the frame, with the pairs of supporting and driving rollers 17, 17' replacing'struts 4-4' and 55 under the wheels revolving them. At the same time, positioning means 18-18 lock pins 9 and 11 of the frame (see FIG. 6).
At this point the motion of carriage 12 starts and accompanies frame 1 in its travel. This movement may be autonomous or may be activated by the aerial conveyor; it must be strictly synchronous with the movement of the aerial conveyor itself.
As soon as the travel of carriage 12 starts, carriage 16 rises up to detach the wheels from the frame putting them into rotation by the motorized rollers (17 and 17).
Simultaneously the spraying of the powder, or the paint starts through the nozzles 19 and 19 that have been adjusted on carriage l6 and directed to the race to be coated. The various movements are controlled by driving means and by travel limiting means of the known type, not shown in the drawing.
At the end of the travel of carriage 12, a second microswitch, not shown in the drawings, starts the reversing cycle during which the machine returns to the start- 7 ing position, that is, near abutment 12, through the following stages: cutting off of the nozzle feed, lowering of carriage 16 and re-positioning of the wheels on the pairs of struts 4-4 and 5-5 of the frame, moving back of carriage 15, and reversing of carriage 12. When a new frame approaches, the cycle starts all over again.
The movements of the carriages of the machine may be realized, as already explained, either by pneumatic, hydraulic or electromechanical systems.
In the case the application of severalpaints or the coating of races of different diameters, are foreseen it will be necessary to provide several spray nozzles, suitably positioned, or a plurality of spraying machines.
In both cases, the wheel-carrying frames will have to be fitted with recognition locators which will activate the proper nozzle or machine.
The supporting and driving rollers for the wheel are adjustable in width, if desired, they may also be automatic, so that they may be adapted to the different widths of the wheels.
In order to avoid any swerving of the frame 1 at the instant of its locking on the carriage l2, guides 23 are provided to act on the lower part of the lower positioning pin 11.
It is advisable to install the machine in a closed ventilated room equipped with a dust felling system.
Obviously, in practice, structurally and functionally equivalent modifications and] variants may be introduced into the above described invention without departing from the spirit and scope of the invention. Thus, for instance, during the coating of races or annular grooves with liquid paints, the pre-heating of the pieces or wheels to be coated may be avoided. Finally, the kinematic motions of the carriages, the driving devices for same and for the spray nozzles may be varied at will and according to requirements.
What I claim is:
1. An apparatus adapted for automatically spray coating an annular seam existing where the rim and disc of a wheel join comprising a frame supported by an aerial conveyor, inclined struts fixed to each side of the frame and adapted to support on their free ends a wheel by its lower peripheral edge in a nonrotating vertical position, and coating devices for spray coating said wheel, said coating devices comprising two horizontally spaced fixed'supports, a first elongated carriage adapted to move along a path parallel to the path of the frame and from the first to the second of said fixed supports at the same speed as the speed of the conveyor during the spray coating operation, a second carriage carried by the first carriage and provided with telescoping means for its alternatively moving towards and from said frame, a third carriage carried by the second carriage adapted to be moved vertically with respect to the frame and provided with a pair of rollers disposed to engage the peripheral edge of the wheel between said struts and to elevate the wheel from the free ends of the struts as the third carriage is elevated and to return the wheel to the struts when the third carriage is lowered, said third carriage being adapted to rotate one of said rollers while the wheel is disengaged from the struts and to thereby rotate the wheel, spray nozzles pointed towards the said seam and actuated while the wheel is rotating and fork-like means for alternatively locking the third carriage to the frame, all three carriages and at least one of said two rollers being adapted to be driven by driving means.
2. The apparatus of claim 1 wherein said frame is suspended from the conveyor by a first rod and a second rod extends downwardly from the bottom of the frame, said two rods being adapted to engage said fork-like means supported by the third carriage whereby the carriages are pulled along between the fixed supports.
3. The apparatus of claim 1 wherein the third carriage projectsfrom the second carriage.
4. The apparatus of claim 1 wherein the spray nozzles areadapted to be moved to direct coating material at different areas of the wheel.
5. The apparatus of claim 1 wherein the third carriage supports a spray nozzle is connected to a source of coating material by a flexible conduit.
6. The apparatus of claim 1 wherein said frame has a rod for securing the top of the frame to the conveyor and a positioning pin below the frame and said third carriage has fork like means disposed to engage said rod and pin to position and lock the frame to the coating apparatus.
7. An apparatus adapted to spray coat an annular seam between a rim and a wheel disc which comprises an aerial conveyor;
a frame for supporting a wheel fixed to the conveyor for movement therewith and comprising vertically disposed spaced rods, a first strut having one end fixed to one of the said rods and inclined inwardly and upwardly therefrom, a second strut having one end fixed to the other of the said rods and inclined inwardly and upwardly therefrom, said struts terminating in ends which are spaced from each other and are adapted to support a wheel vertically thereabove by its rim, positioning pins carried by said frame;
a first carriage mounted between two spaced supports for movement therebetween parallel to the aerial conveyor and synchronized with the movement of the said conveyor;
a second carriage fixed to the first carriage for movement therewith and having a telescoping means adapted to move towards and from the path of the aerial conveyor;
a third carriage fixed to said telescoping means for to and fro movement therewith and for vertical movement relative to a said frame supported by the aerial conveyor in front thereof, means on the third carriage for joining with said positioning pins carried by said frame for positioning a wheel supported on said struts in front of the third carriage, spray coating means supported by the third carriage aimed at said annular seam when said telescoping means is extended, a pair of rollers mounted on said third carriage and positioned where they will move under a wheel supported on said struts while said frame is positioned in front of the third carriage, lift the wheel from the struts with upward movement of the third carriage, rotate the wheel in front of the spray means, and return the wheel to the struts when the third carriage moves downwardly.