Apparatus for application of coating color on a profiled edge or on a straight edge area of a workpiece

Apparatus for application of coating color on a profiled edge or straight edge area of a workpiece, includes a motor-driven applicator roll for coating the workpiece, with the applicator roll having a diameter in the range of 200 to 300 mm for effecting a same coat texture on the narrow surfaces and on the primary surfaces of the workpiece when using a same coating material. The applicator is comprised of two structural assemblies which are connected by a quick-release coupling, with the first structural assembly being formed by a motor-and-gear unit and a mounting, and the second structural assembly being formed by the applicator roll, a plate supporting the shaft of the applicator roll, a doctor being positionally adjustable relative to the applicator roll and a pump for supplying coating color onto the applicator roll.

BACKGROUND OF THE INVENTION 
The present invention refers to an apparatus for application of coating 
color on a profiled edge or on a straight edge area of a workpiece by 
means of an applicator roll which is driven by a motor and a gear unit and 
receives the coating color. 
Conventional applicators of this type include an applicator roll of 
relatively small diameter of approximately 100 mm. Applicator rolls for 
coating primary areas are generally characterized by a relatively great 
diameter. As a consequence, the surface texture of coated primary surfaces 
differs from to the surface texture of coated edge-forming narrow surfaces 
when applying a same coating material. This variation of the surface 
texture is the result of different diameters of the utilized applicator 
rolls and the ensuing uneven coat transfer from the roll onto the surface 
being coated. 
As the edges of workpieces are not always at a right angle perpendicular to 
the primary surface but frequently of arcuated or profiled configuration, 
the use of small roll diameters results in great variations of the 
circumferential speeds of the vertical applicator roll so that 
objectionable coats and waste are experienced. Moreover, the profile depth 
is very limited when using small rolls. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved apparatus 
for application of coating color on a profiled edge or on a straight edge 
area of a workpiece, obviating the afore-stated drawbacks. 
In particular, it is an object of the present invention to provide an 
improved applicator apparatus of the above-stated type by which same 
coating characteristics are effected on the narrow surfaces that form the 
workpiece edges as on the primary surfaces. 
It is still another object of the present invention to provide an improved 
applicator apparatus that can easily be retrofitted in a short period for 
coating a different workpiece. 
These objects, and others which will become apparent hereinafter, are 
attained in accordance with the present invention by providing an 
applicator roll of a diameter which is in the range of 200-300 mm, 
preferably in the range of 230-250 mm. 
The selected roll diameter corresponds to the roll diameter of rolls as 
utilized for coating primary surfaces. Thus, when applying same coating 
material, the narrow surfaces will have a same coat texture as the primary 
surfaces. 
In accordance with another feature of the present invention, the applicator 
includes two structural assemblies which are connected together by a 
quick-release coupling, whereby the first structural assembly comprises a 
motor-and-gear unit and a mounting, and the second structural assembly 
comprises a plate for rotatably supporting the driving shaft of the 
applicator roll, the applicator roll itself, a doctor which is adjustable 
relative to the applicator roll for regulating the amount of coating 
material on the roll, and a pump for supplying coating color on to the 
applicator roll. The quick-release coupling forms a quick change system so 
that the applicator can be retrofitted in a short period for color coating 
a workpiece with different profile edge or different straight edge area. 
Advantageously, the doctor of the applicator is adjustably secured relative 
to the applicator roll and its profiled groove for metering the amount of 
coating color applied on the profiled edge of the workpiece and ensuring a 
smooth color coating. Suitably, the doctor is formed with a projection 
that has a contour resembling the contour of the profiled groove of the 
applicator roll for engagement therein and exhibits, in plan view, a 
tapered end face that faces the supply of coating color. Preferably, the 
tapered end face of the projection is of arcuate configuration, with a 
radius corresponding to the radius of the applicator roll.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Throughout all the Figures, the same or corresponding elements are always 
indicated by the same reference numerals. 
Turning now to the drawing, and in particular to FIG. 1, there is shown a 
vertical, partially sectional view of one embodiment of an applicator 
apparatus according to the present invention for application of a color 
coating on a workpiece 21 that exhibits a profiled edge 20. The applicator 
apparatus is comprised of two structural assemblies, generally designated 
by reference numerals 1, 2 which are joined together by a quick-release 
coupling 3. The structural assembly 1 includes a motor-and-gear unit 
comprised of electromotor 4 and transmission 5 for actuating a drive shaft 
6. As shown in FIG. 5, the first structural assembly 1 further includes a 
mounting, generally designated by reference numeral 9 and provided with a 
circular perforated disk 10 which is rotatably secured to a stationary 
perforated disk 11 via screws 12 for thereby allowing a graduated 
adjustment of the first structural assembly 1 together with the coupled 
second structural unit 2 in direction of double arrow 13 in dependence on 
the selected attachment of the circular disk 10 relative to the stationary 
disk 11. 
The second structural assembly 2 includes an applicator roll 8 which is 
rotatably supported on a drive shaft 7 linked to the drive shaft 6 via the 
quick-release coupling 3, a plate 14 for rotatably supporting the drive 
shaft 7 via rolling bearings 25, a doctor 15 which is retained in a holder 
17 for adjustment in direction to and from the applicator roll 8, as will 
be described furtherbelow, and a pump 16 which is secured to the holder 17 
and supplies coating color to the doctor 15 via inlet 32. 
The applicator roll 8 is made preferably of metal and exhibits a jacket 18 
of flexible material which is formed with a profiled groove 19 for 
engagement by the profiled edge 20 of the workpiece 21. For illustrative 
purposes, the structural assembly 2 is also shown in FIG. 1 in dashdot 
line to depict the disengaged disposition thereof from the structural 
assembly 1. 
In the non-limiting example of FIG. 1, the applicator roll 8 rotates about 
a vertical axis 22, as indicated by arrow 23 in FIG. 3. Arrow 24 
designates the traveling direction of the workpiece 21 relative to the 
applicator roll 8. 
The plate 14 is provided at the end face distant to the workpiece 21 with a 
guide mechanism for securing the holder 17 of the doctor 15 against 
rotation. As shown in particular in FIG. 4, this guide mechanism is formed 
by two spaced rods 26 which extend through bores of the holder 17. Placed 
between the rods 26 is an adjusting spindle 27 which is in mesh with a 
threaded bore of the holder 17 and is rotatably supported in the plate 14. 
At its terminal end distant to the plate 14, the adjusting spindle 27 is 
formed with a knob 28 for allowing manual adjustment of the spindle 27 so 
that the holder 17 and thus the doctor 15 are shiftable in a direction 
transversely to the rotational axis 22 of the applicator roll 8, as 
indicated by arrow 33 in FIG. 1. In addition, the doctor 15 is adjustable 
in a direction parallel to the rotational axis 22 by means of an adjusting 
screw 29 which is in mesh with a threaded bore 30 formed within the doctor 
15 and extending in parallel relationship to the rotational axis 22. 
As best seen in FIGS. 6 and 7, the doctor 15 is formed with a projection 31 
which has a configuration resembling the contour of the profiled groove 19 
of the applicator roll 8. At the side pointing toward the coating color 
supply, the projection 31 is of tapered configuration, with the tapered 
end face being shaped of arcuate configuration, as best shown in FIG. 7. 
Preferably, the radius of the arcuate tapered end face corresponds to the 
radius of the applicator roll 8, and the height of the doctor 15 
substantially corresponds to the height of the applicator roll 8. 
As the doctor 15 is adjustable in two directions, i.e. transversely to the 
rotational axis 22 as well as parallel to the rotational axis 22, the gap 
between the projection 31 and the profiled groove 19 of the applicator 
roll 8 can be adjusted very accurately so that a uniform coat of color on 
the profiled edge 20 of the workpiece 21 is applied. The coating color is 
supplied to the doctor 15 by the pump 16, preferably a diaphragm pump, 
through inlet 32 (FIG. 2). 
As can be seen from FIG. 8, the applicator roll 8 exhibits a relatively 
great diameter which is selected in the range of 200-300 mm, preferably in 
the range of 230-250 mm so that the transfer of color coat (lacqeur, 
varnish) from the surface of the applicator roll 8 onto the narrow surface 
of the workpiece 21 is effected in a careful manner without experiencing a 
sudden break. As its diameter is in the range of 200-300 mm, the 
applicator roll 8 is also usable for coating primary surfaces so that a 
same coating material can be applied for coating narrow surfaces as well 
as primary surfaces to effect a same surface texture. 
While the invention has been illustrated and described as embodied in an 
apparatus for application of coating color on a profiled edge or on a 
straight edge area of a workpiece, it is not intended to be limited to the 
details shown since various modifications and structural changes may be 
made without departing in any way from the spirit of the present 
invention.